From the scientist's writings, a geographer has drawn together this account of South America seen through Darwin's eyes, when that young man, on the verge of self-discovery, circumnavigated the continent as naturalist to the Beagle, a British ship on a charting voyage. Darwin's notes on flora, fauna, and geological formations later provided the basis for his evolutionary theory; but he recorded other phenomena as well, and Hopkin's account focuses on his commentary on daily life and culture ashore. Calling at South American ports in the early 1830's, Darwin saw the new nations in the aftermath of independence, developing since-perpetuated patterns of permanent (military junta-style) revolution and heavy foreign investment. As bearer of the British flat, the Beagle occasionally became involved in vexatious factional politics where it docked; as a carrier of European diseases, it sometimes received a rude quarantine from local authorities. Darwin, who comes across as a sociable, good-natured youth (in contrast to the hypochondriacal recluse of later years) reacted strongly to insults to the Union Jack; but he was also angered by the brutal treatment of slaves and Indian workers. Hopkins gracefully intercuts passages from his subject's notes with historical background and clear, simplified interpretations of contemporary scientific theory. The result is a freshly-angled portrait of the genius as a young man, which should interest the general reader unlikely to peruse Darwin's own Voyage of the Beagle.