It is necessary to make a choice between all the treasures kept by this Library who is the heir of Paris’ apothecaries Library. Two of these are treasures because of their origin. These two books had been printed in Strasburg during the 16th century. The first one is a sample of Dioscorides’ "De Materia Medica" illustrated by magnificent dropped initial capital letters representing an episode of the Bible. It was a gift made by Iohannes du Boys, the apothecary of the brother of King Henry III, the duke of Alençon. This apothecary was also the author of a kind of Pharmacopoeia, entitled, "In Methodum Miscendorum Medicamentorum". The second treasure was a collection of many titles, most of these having been written by Valerius Cordus. This book was a part of a gift of nine, made by apothecaries from Paris. This gift, in 1570, is considered as the foundation of apothecaries’ library. The 17th century is also present with a book unique constituted of 208 pages of preprints of the second edition of Histoire Générale des Drogues by Pierre Pomet, enriched by many notes written by the author himself. This edition was not finished when Pierre Pomet died and it was never published. From the same century, for historical reasons, the Essays by Jean Rey, of 1630, must be selected. The book kept by the library is the one that has been used by Pierre Bayen to rediscover Jen Rey, a forgotten precursor of Lavoisier’s discoveries, and by Gobet to prepare a second edition of the book.