The French text presented in this volume is taken from that of a Leyden edition of 1748, in other words, from that of an edition published in the year and in the place of issue of the first edition. The title page of this edition is reproduced in the present volume. The original was evidently the work of a Dutch compositor unschooled in the French language, and is full of imperfections, inconsistencies, and grammatical blunders. By the direction of the publishers these obviously typographical blunders have been corrected by M. Lucien Arr at of Paris. The translation is the work of several hands. It is founded on a version made by Miss Gertrude C. Bussey (from the French text in the edition of J. Assezat) and has been revised by Professor M. W. Calkins who is responsible for it in its present form. Mademoiselle M. Carret, of the Wellesley College department of French, and Professor George Santayana, of Harvard University, have given valued assistance; and this opportunity is taken to acknowledge their kindness in solving the problems of interpretation which have been submitted to them. It should be added that the translation sometimes subordinates the claims of English structure and style in the effort to render La Mettrie's meaning exactly. The paragraphing of the French is usually followed, but the italics and the capitals are not reproduced. The page-headings of the translation refer back to the pages of the French text; and a few words inserted by the translators are enclosed in brackets. The philosophical and historical Notes are condensed and adapted from a master's thesis on La Mettrie presented by Miss Bussey to the faculty of Wellesley College.