For practical purposes it is often assumed that the latest edition of a modern book published during the author’s lifetime may be treated as the original. This is a simplification. The actual author’s original may have been a manuscript or a typescript or a recording; in the process of publication it has passed through several stages of transmission, including possibly storage in a computer, at any one of which errors have necessarily occurred. Experience teaches that some errors will survive uncorrected in the published version. Further errors are likely to occur if a book is reprinted. Even an edition revised by the author is not to be regarded as textually definitive. Errors committed and overlooked by the author himself may be corrected by the critic in appropriate cases. Special problems are posed by an author’s second thoughts, whether preserved in his books and papers or incorporated in editions revised by him; recent research has shown that authorial revision in modern printed books has been underestimated. The extent to which a critic is free to choose between authorial variants on aesthetic grounds is a matter of debate.

Books published before the 19th century pose essentially similar problems in a more intractable form, as may be seen in the case of Shakespeare. No manuscript of any of Shakespeare’s plays survives, and there were substantial intervals between the dates of composition and the first printed versions, in which unauthorized variation clearly occurred. For Shakespeare’s plays, indeed, the very concept of an author’s original may be misleading. Elizabethan printers clearly had little regard for strict textual accuracy, so that allowance must be made not only for error but for deliberate alteration by compositors; thus the textual criticism of 16th- and 17th-century books must include a study of the practices of early printers.

Books transmitted in manuscript

Nearly all classical and patristic texts, and a great many medieval texts, fall into this category. Every handwritten copy of a book is textually unique, and to that extent represents a separate edition of the text. Whereas the characteristic grouping of printed texts is “monogenous” (i.e., in a straight line of descent), that of manuscript texts is “polygenous” or branched and interlocking. The critic is in principle obliged to establish the relationship of every surviving manuscript copy of a text to every other. The difficulty and indeed the feasibility of this undertaking varies enormously from case to case. The following extremes embrace a wide range of intermediate possibilities. (1) The authority for a text may be a single surviving copy (e.g., Menander, Dyscolus) or a copy that can be shown to be the source of all other copies (e.g., Varro, De Lingua Latina) or an edition printed directly from a copy now lost (e.g., the work of the Roman historian Velleius Paterculus); or a text may be transmitted in scores of copies whose interrelationships cannot be exactly determined (e.g., Claudian, De raptu Proserpinae). (2) The interval between the original and the earliest surviving copies may be very short (e.g., the French medieval poet Chrétien de Troyes) or very long (e.g., the Attic tragedians). (3) A tradition may be “dynamic”—i.e., the text may have been copied and recopied many times even in a short time (e.g., Dante’s La divina commedia); or it may be “static”—i.e., the number of transmissional stages even over a long period may have been few (e.g., Epigrammata Bobiensia a Latin translation of Greek epigrams). (4) A text may be a religious or literary work that was respectfully treated by copyists and protected by an exegetical tradition (e.g., the Bible, the Latin poet Virgil); or a popular book that was exposed to correction, glossing, and amplification by readers (e.g., the Regula magistri [“Rule of the Master,” a Latin work related to the Rule of St. Benedict] and much medieval vernacular literature). (5) A text may have been written and transmitted after the establishment of a scholarly tradition, or it may show signs of “wild” and arbitrary variation dating from an age in which standards of exact verbal accuracy were low. To this extent all Greek books written before the establishment of the Alexandrian library (see below History of textual criticism) were exposed to the hazards associated with oral transmission.

Books transmitted orally

Many texts have been orally transmitted, sometimes for long periods, before being committed to writing, and much textual variation may be attributable to this stage of transmission. Often in such cases the critic cannot attempt to construct an “original” but must stop short at some intermediate stage: thus the edited text of Homer means in practice the closest possible approximation to the text as established by the scholars of Alexandria. The length, complexity, and fidelity of oral traditions varies enormously. The text of the old Indian Rigveda was transmitted orally almost without variation from very ancient to modern times, whereas much old French epic and Provençal lyric has descended in variant redactions for which a common source may be postulated but cannot be reconstructed. Sometimes this is attributable not to spontaneous variation but to deliberate reworking, whether by the author, as appears to be the case with the three (or perhaps four) versions of the English poem Piers Plowman, or by later revisers, as with the four versions of Digenis Akritas (a Greek epic). The distinction, however, is not always easy to draw. These considerations apply to a wide range of texts from ancient Hebrew through Old Norse to modern Russian, but they are especially important for medieval literature. In this field perhaps more than in any other the critic’s aims and methods will be dictated by the character of the oral tradition, the stage at which it attained a more or less fixed form in writing, and the attitude of copyists in a particular genre to precise verbal accuracy. A problem of particular difficulty and importance is posed by the Greek New Testament. Though the text appears to have been transmitted from the first in writing, the textual variations are in many ways analogous to those of an oral tradition, and it is commonly held that the essential task of the critic is not to try to reconstruct the “original” but to isolate those forms of the text that were current in particular centres in the ancient world.