Books have led some to learning and others to madness, when they swallow more than they can digest.

Francesco Petrarca (1304-1374) Italian scholar and poet [a.k.a. Petrarch]
Remedies for Fortune Fair and Foul [De Remediis Utriusque Fortunae] [tr. Elton (1893)]

Alt. trans.: "Books have brought some men to knowledge, and some to madness. whilst they drew out of them more than they could digest." [tr. Dobson (1791)]

Alt. trans.: "Books have led some to knowledge and some to madness, who drew from them more than they could hold." [tr. Rawski (1991)]