This is a classic of Renaissance botany. It is the Latin translation, by David Kyber, of the third edition of Hieronymus Bock's herbal, Kreüter Buoch (Strassburg: Wendel Rihel, 1551). Tragus is the Latinized form of Bock. The preface by Conrad Gessner is a bio-bibliography of the history of botany and materia medica up to the mid-16th century. (The best study is Brigitte Hoppe, Das Kraüterbuch des Hieronymus Bock [Stuttgart: Anton Hiersemann, 1969).