The Book of Discoveries covers a wide range of historical expeditions spanning three millennia, from the Phoenician voyages of antiquity to modern explorations of space and the deep sea. It focuses on important explorers such as Leif Eriksson, Christopher Columbus, Vasco da Gama, and Ferdinand Magellan, and their journeys to the Americas, India, and the first circumnavigation of the globe. The book also explores the adventures of great naturalists like Alexander von Humboldt in South America, polar expeditions to the Arctic and Antarctic, and research voyages through Africa and North America.