Libellus de lacte, et operibus lactariis, philologus pariter ac medicus; cum Epistola ad Iacobum Avienum de montium admiratione.

The first book on Alpinism and mountaineering. Digital facsimile from the Hathi Trust at this link. English translation by H. B. D. Soulé as Conrad Gesner: On the admiration of mountains; the prefatory letter addressed to Jacob Avienus, Physician, in Gesner's pamphlet "on milk and substances prepared from milk first printed at Zurich in 1543. A description of the Riven Mountain, commonly called aMount Pilatus, addressed to J. Chrysotome Huber, originally printed with another work of Gesner's at Zurich in 1555. San Francisco: The Grabhorn Press, 1937.