In ancient times, a total solar eclipse was a time of fear and wonder. The scientific revolution inaugurated by Copernicus relegated these eclipses to the category of ‘understood’ phenomena. Astronomers still relish their occurrence, but because of the opportunity they provide to carry out observations that would be impossible by day. This book is about a famous example of this opportunism: the two expeditions to observe the bending of starlight by the Sun as predicted by Einstein from Sobral in northern Brazil and the island of Principe in the Gulf of Guinea during the eclipse of 29 May 1919. As well as providing an understanding of the key ideas of Einstein’s theory, this story offers fascinating insights into the sociological conflicts between ‘Big Science’ and popular culture that are as real today as they were 80 years ago.