As Charles Darwin cruised the world on the HMS Beagle, he had access to an unusually well-stocked 400-volume library. That collection, which contained the observations of numerous other naturalists and explorers, has now been recreated online. As of today, all of more than 195,000 pages and 5000 illustrations from the works are available for the perusal of scholars and armchair naturalists alike, thanks to the Darwin Online project. The Beagle’s library included such influential reference texts as Charles Lyell's Principles of Geology, as well as the writings of James Cook, Alexander von Humboldt, and Thomas Pennant (from whose 1793 book, History of Quadrupeds, this picture of a camel is taken). Atlases and books on travel, natural history, and geology made up most of the collection. But it had a few works of literature as well, including John Milton's Paradise Lost. The Beagle library was dispersed when the voyage ended in October 1836. Scholars had previously identified 132 works as probably in the library based on Darwin's writings. Science historian John van Wyhe, of the National University of Singapore, identified additional likely volumes by scouring Darwin's field notebooks and the writings of other crew members for hints. The entire library—181 works in 404 volumes—includes works with illustrations digitized for the first time.