Alfred Wegener was a German meteorologist, explorer, and geologist. In his 1915 book Die Entstehung der Kontinente und Ozeane ("The Origin of Continents and Oceans") he set forth what became known as "Wegener's hypothesis," or theory of continental drift, whose developments were in succeeding decades to revolutionize our view of the planet we live on.

Wegener's ideas crystallized in 1914 as he was recuperating in a military hospital from an injury suffered as a German soldier during World War I. While bed-ridden, he had time to develop an idea that had intrigued him for years. Like others before him, Wegener had been struck by the remarkable fit of the coastlines of South America and Africa. But, unlike the others, to support his theory Wegener sought out many other lines of geologic and paleontologic evidence that these two continents were once joined. During his long convalescence, Wegener was able to fully develop his ideas into the theory of continental drift. See also plate tectonics.