For more than 600 years, Western civilization has relied on exploration to learn about a wider world and universe. The Great Ages of Discovery details the different eras of Western exploration in terms of its locations, its intellectual contexts, the characteristic moral conflicts that underwrote encounters, and the grand gestures that distill an age into its essence.

Historian and MacArthur Fellow Stephen J. Pyne identifies three great ages of discovery in his fascinating new book. The first age of discovery ranged from the early 15th to the early 18th century, sketched out the contours of the globe, aligned with the Renaissance, and had for its grandest expression the circumnavigation of the world ocean. The second age launched in the latter half of the 18th century, spanning into the early 20th century, carrying the Enlightenment along with it, pairing especially with settler societies, and had as its prize achievement the crossing of a continent. The third age...