Tobias Kruger explores the discovery of the Ice Ages, how the idea was received, and what further research it stimulated. The approach used in Discovering the Ice Ages is uniquely sweeping. The contemporary debates on the subject are compared from an international perspective. Kruger retraces the arguments advanced from the middle of the 18th century to the threshold of the 20th century. The positions held by defenders of the glacial theory as well as those by its most important opponents are set within the context of the then current understanding of geology. In an interdisciplinary overview Kruger then focuses on the impetus gained from early ice-age research. The most prominent examples worth mentioning are the discovery of trace gases and the greenhouse effect.