James Sloss Ackerman, one of the leading historians of art and architecture, was born in San Francisco in1919. He taught at Berkeley and then at Harvard until 1990. During the Second World War he served in the US Army in Italy. This allowed him to improve his knowledge of the Italian Renaissance which will then become his major area of expertise. His books are considered classics in their field, both in terms of rigor and of method: a monograph on architecture, the biography of an artist, the study of a particular architectural style. The first is exemplified by The Cortile del Belvedere (1954). The second is well illustrated by his fundamental works in the sixties on the architectural works by Michelangelo and Palladio. Finally the third is to be found in The Villa: Form and Ideology of Country Houses (1990). In this Ackerman analyses the common characteristics as well as the specific elements of this type of building, from the Roman villa to Wright's Waterfall House. For all the great variety of forms that the villa has taken on over time, it appears that the underlying ideology has remained substantially unchanged from its origins to our days. In addition to these major works Ackerman has also written hundreds of essays on the history of Renaissance architecture, studies on the relation between art and science and on the intellectual, moral and social foundations of teaching.