José de Acosta, Historia natural y moral de las Indias (Seville, 1590)

The Jesuit book that treated the Americas as a problem in natural philosophy rather than a catalogue of marvels. Printed at Seville in 1590, it argues from the distribution of wild animals that the two land masses must join somewhere unexplored and that people walked over; it gives the first sustained clinical account of altitude sickness, and gets the cause right; and it reads Andean knotted cords as a system of record.