No shadow of a doubt : the 1919 eclipse that confirmed Einsteins theory of relativity In 1919 British scientists led extraordinary expeditions to Brazil and Africa to test Albert Einstein’s revolutionary new theory of general relativity in what became the century’s most celebrated scientific experiment. The result ushered in a new era and made Einstein a global celebrity by confirming his dramatic prediction that the path of light rays would be bent by gravity. Today Einstein’s theory is scientific fact. Yet the effort to “weigh light” by measuring the gravitational deflection of starlight during the May 29 1919 solar eclipse has become clouded by myth and skepticism. Could Arthur Eddington and Frank Dyson have gotten the results they claimed Did the pacifist Eddington falsify evidence to foster peace after a horrific war by validating the theory of a German antiwar campaigner In No Shadow of a Doubt Daniel Kennefick provides definitive answers by offering the most comprehensive and authoritative account of how expedition scientists overcame war bad weather and equipment problems to make the experiment a triumphant success.