Writing about engineering went through one of its decisive stages, on the way from the ancient treatise to the modern textbook, during the 15th century. Mariano Taccola of Siena is a key figure in this development, and his "De Machinis" of 1449 culminates a lifetime devoted to the composition of countless engine drawings and technical texts. It is a record of machines for civil and military engineering, hydraulics, mills and tunnels. The autograph...