In 1915 Stanley Spencer reported for duty in the Royal Army Medical Corps at Beaufort Hospital, Bristol, England. The war years were only his second time spent away from his home in Cookham, Berkshire. Swan Upping at Cookham holds an important place within his oeuvre, as it was begun shortly before Spencer left for Bristol and completed only after his return in 1919. The title refers to an annual event held on the River Thames when young swans are collected and marked; Cookham Bridge is seen in the background. The idea for the work came to Spencer while he was in church. He could hear the activities of people outside, which inspired him to transfer the spiritual atmosphere of the church on to the secular landscape of Cookham. The unfinished work—the top two-thirds were completed before he left—haunted Spencer during the war, but once home he found it hard to complete. (Tamsin Pickeral)

Celebes (1921)

German-born artist, sculptor, and collagist Max Ernst formed the German Dada group in Cologne in 1920. He left Germany in 1922 to join the Surrealist group in Paris. There he invented the technique of “frottage.” Celebes dates from a period in Ernst’s career when he combined Dada and Surrealist aesthetics. This, his first large-scale picture in Cologne, evolved out of his use of collage to create unexpected combinations of images. At the center of the painting stands a gigantic figure that seems to resemble both an elephant and a boiler; it appears to have a trunk, tusks, and pipes sprouting from it. This monstrous figure, apparently inspired by a photograph of a communal corn-bin in Sudan, is surrounded by several unrecognizable objects, including a headless female mannequin. As a Dadaist, Ernst often reused found images, which he combined with others to create original, imaginary works. (Julie Jones)

Pietà or Revolution by Night (1923)

In 1911 the German Surrealist painter Max Ernst met the artist August Macke, with whom he became close friends, and joined the Rheinische Expressionisten group in Bonn. His first exhibition was held in Cologne in 1912 at the Galerie Feldman. That same year, he discovered works by Paul Cézanne, Edvard Munch, Pablo Picasso, and Vincent van Gogh, who made a deep impression on his own artistic development. The following year he traveled to Paris, where he met Guillaume Apollinaire and Robert Delaunay. In the early 1920s, he participated in the Surrealist movement in Paris, and he is regarded as one of its leaders. Pietà or Revolution by Night was painted in 1923, a year before André Breton published the first Manifesto of Surrealism. The Surrealists sought to find a means to depict not only the outer reality but the working of the human mind, and were influenced by Sigmund Freud’s theory of the unconscious. In this painting, Ernst replaced the traditional figures of the mourning Virgin Mary holding the body of her crucified son Jesus in her arms by a portrait of himself held by his bowler-hatted father. Although no one can give a definitive analysis of the image, it has often been regarded as an expression of the troubled relationship between Ernst and his father, who being a fervent Roman Catholic had previously denounced his son’s work. Both appear as statues, perhaps reflecting the frozen nature of their relationship, yet the choice of the pose of the pietà suggests Ernst’s desire for change and paternal affection. (Julie Jones)

Composition with Yellow, Blue and Red (1937–42)

Piet Mondrian is one of the most important figures in the development of abstract art. Mondrian was keen to develop a purely nonrepresentational mode of painting, based on a set of formal terms. Underlying Mondran’s ambitions for painting was the aim to express a “pure” reality. His style, now known as Neoplasticism, did not refer to the external, recognizable world. Having removed all imagery from the canvas, what are conventionally seen as the key elements of painting—line, form, hue—were now mobilized to serve very different ends, namely the embodiment of “plastic expression.” To this end, Mondrian was able to restrict himself to straight lines and basic colors. In Composition with Yellow, Blue and Red, 1937–42 he organizes the composition around a series of vertical and horizontal lines that overlap to form a grid. Four discrete areas of primary color are “weighted” so that color functions as a form of counterbalance in relation to each line’s ascribed role. Composition with Yellow, Blue and Red is a mature representation of this approach. Mondrian began the piece while he was living in Paris; he went to live in London in 1938, then moved to New York two years later, where the painting was completed. In New York, the artist took a further step in his program of formal experimentation, by giving complex color planes precedence over lines. The significance of this work rests in its ability to take what is fundamental to painting and create a reality entirely in accordance with Mondrian’s quest for plastic expression. (Craig Staff)

Child with a Water-Melon (c. 1947–48)

Barcelona-born Antoni Clavé fought with the left-wing Republicans in the Spanish Civil War of 1936–39. After their defeat, he fled to France. In 1944 he met Pablo Picasso, and Child with a Water-Melon suggests that Clavé was strongly influenced by his compatriot. The child here emulates that of Picasso’s depiction of his son Paulo as a harlequin in 1924. Harlequins featured in many of Picasso’s early works, and the harlequin is a character of the commedia dell’arte, which had been part of Barcelona street theater and carnivals. This is a fitting subject for Clavé, whose oeuvre included stage sets, theatrical costume design, and poster design. Yet Clavé’s harlequin is a melancholy figure; the colors of his diamond-patterned costume are dark. He looks like a hungry and grateful beggar, ready to eat the fruit in his hands with its rich red flesh, reflecting the blood spilled in the Spanish Civil War. (Lucinda Hawksley)

Portrait Group (1951)

Rodrigo Moynihan’s remarkably diverse artistic output includes abstract paintings, portraits, still lifes, landscapes, and figures in oils, gouache, watercolors, pen, and wash. Unlike the tide of Realist painters who gradually morphed into abstract artists, Moynihan was producing experimental works in the 1930s. These paintings, which focused on tone and color, were heavily influenced by Claude Monet, Paul Cézanne, and J.M.W. Turner. Moynihan began making realistic, tonal, and figurative images during the late 1950s, and during the 1970s he focused on portraits and still lifes painted in an anachronistically academic style with a muted palette and a sense of pictorial economy. Toward the end of his life, he was simultaneously creating abstract canvases and landscapes influenced by Chinese calligraphic tradition. Portrait Group exemplifies the sobriety and physiological sensitivity of Moynihan’s Realist period. The painting is alternately titled The Teaching Staff of the Painting School at the Royal College of Art, 1949–50, and it represents, from left to right: John Minton, Colin Hayes, Carel Weight, Rodney Burn, Robert Buhler, Charles Mahoney, Kenneth Rowntree, Ruskin Spear, and Rodrigo Moynihan himself. The narrative relationships between the figures and their position in the space would be compelling without any knowledge of Moynihan’s sitters or their own work, but the fact that this is a painting of painters adds the intriguing question of whether his sitters harbored competitive feelings when they saw the fine result produced by Moynihan’s flexible talent. (Ana Finel Honigman)

Painting, 23 May 1953 (1953)

Pierre Soulages was a member of the group of artists practicing Tachisme. This style concerned mark-making and was influenced by the calligraphy of the East. Their dynamic work expressed the physical procedure of painting as much as the resulting image. Soulages experimented with abstraction, using long brushstrokes of black paint against light backgrounds. The title of this work refers to the date it was completed. Smooth, almost slick slabs and swathes of rich, dark paint overlay each other, creating a latticelike network of flat bands that dominate the image. The sweeping brushstrokes are reminiscent of Asian scripts with their gestural and energetic calligraphic shapes and the strong marks emphasize the process of painting. Despite the small size of the canvas, the shiny black paint commands attention, intensified by the small gleams of light colors glinting through the darkness. (Susie Hodge)

Man Woman (1963)

In the 1960s Allen Jones explicitly drew from culturally unacceptable sources—John Willie’s Bizarre magazine, Eric Stanton’s bondage cartoons, brown-paper-bag-wrapped porn—all of which led to his controversial apotheosis, the 1969 life-size statues of women-as-furniture (Chair, Hat Stand, Table). Man Woman is one of a series of paintings exploring transgender identity and the breaking down of sexual stereotypes. Here, Jones fuses the male and female archetypes, both headless but, in his powerful green-against-red polarizing color scheme, he subverts cliché in dressing the man in a red shirt (red being redolent of erotica: lipstick, rouge, red-light areas) against the green tones of the woman. Jones’s brushwork is unmannered, loose, and free; the colors vivid and bold. He is an unapologetic sensualist, up there with Henri Matisse and Raoul Dufy. (Paul Hamilton)

Cadmium with Violet, Scarlet, Emerald, Lemon and Venetian: 1969 (1969)

Patrick Heron resisted the drive toward abstraction in the 1950s until the end of the decade, when he started producing canvases composed of horizontal blocks of color. Before then, he had been making muddled and often muddy Cubist images. But once he cleared his palette, he began incorporating other shapes and more complex compositions, and he produced some of the genre’s most moving and magnificent canvases. Circles and circular forms became his signature, but color was his obvious area of interest. His balancing of contrasting colors far surpassed other Abstract painters, and his technique created the illusion of soft textures and pliant surfaces. As a young man, Heron worked as a textile designer for his father’s firm. His understanding of design and fabric is evident in his method of composing the beautiful, rich patches of pure color saturating his canvases. Cadmium with Violet, Scarlet, Emerald, Lemon and Venetian: 1969 is a perfect example of how Heron’s early intimacy with textiles informed his mature work. The painting gives the impression of being a silkscreen, as the color is absorbed into the canvas, allowing the reds, greens, and purples to meld together yet still arrest the eye. Heron published extensively as a critic, but he temporarily stopped writing criticism once he began painting in an abstract mode. Writing arguably hobbled Heron’s creativity and his ability to emote on canvas. His painting blossomed after he broke from criticism, as this extraordinary work testifies. (Ana Finel Honigman)

Dry Creek Bed, Werribee Gorge I (1977)

Fred Williams was undoubtedly one of the most significant and influential Australian artists of the 20th century. Born in Melbourne, he studied for a while at the National Gallery of Victoria Art School before traveling to London in 1951. There he worked as a picture framer and studied at the Chelsea School of Art and the Central School of Arts and Crafts. While in London, Williams produced a series of scenes of music halls. On his return to Australia he developed his skills as a printmaker and turned his attention to depicting the landscape of his native country in new and extraordinary ways. It was not long before his unique vision began to emerge, and he tried to convey through his paintings the enormity and timelessness of the Outback. The use of color and subtle markings give an eerie sense of soaring to a great height. Werribee Gorge is located in Victoria, Australia, and it is a spectacular natural phenomenon. Such a significant feature takes pride of place in this painting, and it is illuminated by the parched colors and mysterious markings. Werribee is a word of the Australian Aboriginal people meaning “backbone,” and the curving line suggests, perhaps, the outline of a snake. Williams’s paintings became sparer as he progressed. These later landscapes are excellent examples of an artist who has, after a long journey, found his authentic voice. (Stephen Farthing)

Black Sea (1977)

Philip Guston can best be understood as two painters: before and after. The “before” Guston was a comfortably successful Abstract Expressionist. His canvases from the 1950s usually consisted of swatches of solid red, black, or white concentrated in the picture’s center. By contrast, a repeated cast of pink cartoon figures and objects dominated his “after” work. In tone, the particular pink that became his signature was reminiscent of old chewing gum, but, despite the sugariness of this association, little was sweet in Guston’s later canvases. These paintings are populated by stained coffee cups, cigarette butts, dirty boots, messy beds, and lonely men whose puffy pink faces are reduced to big, frightened eyes and mouths plugged up by cigarettes. Guston’s embrace of one of these diametrically oppositional styles of painting and his rejection of the other was a defining break from the cultish reverence for abstraction that ruled the art world of the 1950s. Though painted with a darker, more somber palette than was typical of this time in his career, Black Sea is otherwise emblematic of Guston’s mature, iconoclastic work. Over the sea is a blue sky streaked with light, like the sky at dawn, but, instead of the sun, the heel of a shoe rises ominously above the horizon line. (Ana Finel Honigman)

The Citizen (1981–83)

Collage artist and painter Richard Hamilton is considered by many to be the first Pop artist. Born into a working-class London family, he dropped out of school and worked as an apprentice electrician while taking evening art classes at Central Saint Martins. He then entered the Royal Academy, but he was expelled for failing courses. After enlisting in the military, Hamilton joined the Slade School of Art for two years before exhibiting independently in London. Greatly inspired by Marcel Duchamp, he befriended him and in 1966 curated the first retrospective of Duchamp’s work to be shown in the UK. Like Duchamp, Hamilton borrowed images and references directly from mass culture and recontextualized them to highlight their political, literary, or social meaning. Inspired by a documentary on the “dirty protest” by republican prisoners at the Maze prison in Northern Ireland, The Citizen depicts a messianic-looking protester standing in a prison cell smeared with feces. During the Maze protest, inmates who demanded to be classified as political prisoners refused to wash or wear regulation clothing and smeared their cells with excrement. Hamilton represents feces as soft, brown washes of color surrounding the bedraggled yet heroic central figure. The image is “shocking less for its scatological content,” Hamilton asserted, “than for its potency…the materialization of Christian martyrdom.” The painting’s title is borrowed from the nickname given to a character from James Joyce’s Ulysses. (Ana Finel Honigman)

Paul (1984)

Sean Scully is one of the finest abstract painters of the late 20th and early 21st centuries. His signature motif, the stripe and all its variants, runs throughout his extraordinarily rich body of work, a testament to the artist’s unstinting belief in the transcendent power of repetition. Starting during his student days at the University of Newcastle upon Tyne, Scully followed a consistently individual path in an effort to reinstate the primacy of abstraction over figuration. The artist repeatedly argued that abstraction became divorced from the real world, and a desire to imbue abstraction with profound human feelings lies at the core of his ambition. Painted in memory of Scully’s son following his untimely death, Paul declares its expressive intentions in the most immediate terms. Its sheer scale evokes a scene of great physical activity in the studio, where the painting’s variously colored horizontal and vertical components have been built up on the surface of the canvas. Like so many of the artist’s works from the mid-1980s, Paul includes a section of panel that stands proud of its neighbors. This device brings the painting away from the wall and invests it with dramatic sculptural and architectural properties. Although the figure plays no part in Scully’s resonant paintings, the forms and colors are charged with an especially earthy and emotional presence. (Paul Bonaventura)

St. John (1988)

Born in 1932 in Dresden, where he trained as a painter, Gerhard Richter moved to West Germany just before the Berlin Wall was erected in 1961 and studied at the Düsseldorf Academy. He constructed a practice that stood apart from both the established conventions of painting and the popular voices of the time that predicted painting’s ultimate demise. Characterized by breaks in style that do not follow the usual linear chronology from figuration to abstraction, his bodies of works—designated by the artist as “figurative,” “constructive,” and “abstract”—overlap, and paintings produced in the same period often differ dramatically in their appearance and method. These aesthetic contradictions are central to Richter’s approach, as he rejects any singular idea of style as an unnecessary limitation on his practice as an artist. St. John is one of a series of abstract paintings known as the “London Paintings,” named after chapels in Westminster Abbey. It was generated from an initial painting to which a further layer of paint was applied. Richter then scraped and dragged the surface with spatulas to reveal previous layers. The mixed layers result in a painting that can be neither predicted nor completely controlled and that bears no resemblance to the original image. Richter invoked an affinity to music in these paintings, underlining their illusiveness and resistance to description. (Roger Wilson)

Half-Brothers (Exit to Nowhere–Machiavellian) (1994–95)

Like art, horse racing subscribes to its own set of invented rules, and so it seemed natural to British artist Mark Wallinger that he should work with an activity whose artificiality mirrors the fabrications of his chosen profession. He received a Turner Prize nomination in 1995 following his unorthodox A Real Work of Art, where he bought a racehorse and called it an artwork, in the tradition of a Marcel Duchamp readymade. In addition to acknowledging that the recognition of any object as an artwork involves a leap of faith on the part of the viewer, A Real Work of Art touched on the unsettling consequences aroused by the prospect of eugenics. This theme found another outlet in a related group of four naturalistic paintings in which the front half of one famous British racehorse is paired with the rear end of its maternal and equally famous blood-brother: Diesis with Keen, Unfawain with Nashwan, Jupiter Island with Precocious, and—in this painting in the Tate collection—Exit to Nowhere with Machiavellian. Taken together, these life-size paintings of racehorses reflect on the complexity of the relationship between a parent and its offspring and the crucial role played by stud farms in determining the outcome of any thoroughbred breeding program. In his exploration of the issues of cultural and personal identity, and in his works that relate to horse racing, Wallinger created one of the most important bodies of work to come out of the UK on the subject of self and belonging. (Paul Bonaventura)