Max Planck came to prominence after proposing the quantum idea in 1900 and rose steadily to the forefront of scientific leadership in Germany, which retained its lead in science especially in physics, chemistry, and mathematics during the first several decades of the 20th century. A close colleague of Einstein and most major continental scientists of his period, Planck fought a losing battle against overwhelming odds by defying the Nazi regime. Heilbron's biography carefully details the life of this courageous, humane, and brilliant scientist.