I quattro libri dell'architettura (The Four Books of Architecture) is an Italian treatise on architecture by the architect Andrea Palladio (1508–1580). It was first published in four volumes in 1570 in Venice, illustrated with woodcuts after the author's own drawings. It has been reprinted and translated many times (often in single-volume format). Book I was first published in English in 1663 in a London edition by Godfrey Richards. The first complete English language edition was published in London by the Italian-born architect Giacomo Leoni in 1716-1720.
Palladio founded an architectural movement which takes its name from him, Palladian architecture. I quattro libri dell'architettura contains Palladio's own designs celebrating the purity and simplicity of classical architecture. Some of these ideas had gotten no further than the drawing board while others, for example villa plans, had been successfully built. The book's clarity inspired numerous patrons and other architects. Palladian architecture grew in popularity across Europe and, by the end of the 18th century, had extended as far as North America. Thomas Jefferson, president of the United States, was a keen admirer of Palladio and once referred to the book as "the Bible". The Four Books was used to inform his own work as the architect of Monticello and the University of Virginia and also architect William Buckland's at the 1774 Hammond-Harwood House in Annapolis, Maryland.