Bernard Forest de Belidor (born 1698, Catalonia, Spain—died Sept. 8, 1761, Paris, France) was a military and civil engineer and author of a classic work on hydraulics.
After serving in the French army at an early age, he developed an interest in science and worked on the measurement of an arc of the Earth. The study of ballistics also attracted him, and he became professor of artillery at the French military school at La Fère and eventually rose to become inspector of artillery. He wrote several notable books on engineering, artillery, ballistics, and fortifications, but his fame rests primarily on Architecture hydraulique, in four volumes (1737–53), covering engineering mechanics, mills and waterwheels, pumps, harbours, and sea works.