Although he was the first professor of Tibetan in Europe as well as the chair of Sanskrit at the Collège de France, Philippe-Édouard Foucaux (1811-1894) is little remembered today; Bernard le Calloc’h, in a series of biographical articles on Foucaux, has described him as “un Angevin oublié.” Nevertheless, Foucaux’s published works, especially those on Mahāyāna Buddhism, are well represented in libraries and still studied. On the other hand, a number of his unpublished works, preserved at the Bibliothèque nationale de France, have lain untouched for a century. This article reunites the “Foucaux collection,” the books and manuscripts from Foucaux’s library that were acquired by the BnF in various purchases and donations over time. Of particular interest are his marginal annotations — they provide a window into the mind of a 19th-century Indologist and Tibetologist as he encountered, for the first time, the extraordinarily alien traditions of the Orient.