  During the years from 1917 to 1921, A.S. Eddington was intensely occupied
with Einstein's general theory of relativity and the epic eclipse expedition
which confirmed one of the theory's predictions. During the same period, he
investigated the old problem of why the stars shine, which led him to suggest
two different subatomic mechanisms as the source of stellar energy. One of them
was the annihilation of matter and the other the building-up of helium from
hydrogen. This paper is concerned with Eddington's work in this area, a line of
work to which he returned on and off during the 1920s but then abandoned. His
decision to stop working on the stellar energy problem coincided with the first
attempts to understand the problem in terms of nuclear physics and quantum
mechanics. Why did Eddington not follow up his earlier work and why did he
ignore the contributions of the nuclear physicists which in the late 1930s
resulted in the first successful theories of stellar energy production?
