Identifying gaps in knowledge is the first duty of any historian who sets out to understand the past. It is impossible fully to understand our forebears without some idea of what they did not know: the history of ignorance is an indispensable part of history itself. Here Alain Corbin focuses on our planet, exploring its mysteries past and present, and the intensity and eventual decline of the modes of terror and wonder it aroused. For thousands of years, humans knew nearly nothing about the earth. Certain locations on the map simply read ‘Terra Incognita’. Corbin recounts the many errors and uncertainties that littered the paths we followed in the attempt to discover the secrets of our blue planet, with a particular focus on the eighteenth and nineteenth centuries when the mysteries of volcanoes, the polar regions, glaciers, the stratosphere and the oceans began to be uncovered. While ignorance stimulated our ancestors’ imagination, Corbin’s history of ignorance reawakens our thirst for knowledge and changes our view of the world.