The Libro de Cosmographía of 1538 was the first of four sixteenth-century cosmographies written by Pedro de Medina, yet it was the last to be discovered. The 62-page document turned up quite by chance (in 1959) among a collection of 2,000 volumes that had been purchased in 1817 by the Bodleian Library at Oxford, England. Its translation, editing, and accompanying commentary by Ursula Lamb are, in and of themselves, superb pieces of scholarship. This, as do each of her other published works, reveals a deep understanding of the times, places, and people that created such exceptional books as the Libro de Cosmographia.

A Navigator’s Universe consists of three parts, a section of notes pertaining to the translation, an extensive bibliography, and an index. Part I (“Introduction”) is further subdivided into three sections: (1) “A Cosmographer’s World,” (2) “The Author; El Maestro Pedro de Medina,” and (3) “The Cosmographic Manuscripts by Pedro de Medina: A Commentary.” Part II is a black-and-white facsimile reproduction of the original manuscript. Part III is the translation of the Libro de Cosmographía.

The Libro de Cosmographía is written in dialogue form—an ancient technique. There are two questioners who are answered by Medina. One of the questioners, a pilot, is interested in technical matters (tides, altitudes of stars, distance, direction, etc.); the other, an educated layman or licenciado, is more philosophical (What is an hour, a day, a week, or a month? What is an eclipse? What is wind? Why do not people on the bottom of the earth fall?). All told, 82 intriguing questions are posed. The maestro’s answers are direct and skilled. The style does not permit a lengthy narrative, and the result is unusual clarity and a dramatic insight into the mariner’s knowledge of the period.

Medina was born in 1493, probably in Medina but maybe in Seville. He took holy orders before 1538, while he was serving as a tutor in the household of the dukes of Medina Sidonia. The Libro de Cosmographía was submitted to the Royal Council of the Indies in order to support his application for a cosmographer’s license, which was granted on December 20, 1538. From then until his death in 1567, the maestro lived and worked in Seville. He was a senior member of the scientific office of the pilot major (which controlled the pilots and masters involved in the voyages to America, as well as their equipment). As a cosmographer it was Medina’s job to collect and interpret new knowledge and assimilate it with all that was useful from the old. Cosmography was, in the 1500s, a mixture of astronomy, geography, and hydrography. Today virtually everything considered by Medina falls within the general field of physical geography.

As Ursula Lamb so aptly expresses it (p. 30): “Pedro de Medina put into his book the world of the discoveries. Although we no longer see our universe in the Libro de Cosmographía, we can find it in the world in which its author lived.”