Peter Gabriel Bergmann was a German-American physicist best known for his work with Albert Einstein on a unified field theory encompassing all physical interactions. He also introduced primary and secondary constraints into mechanics. After obtaining his Ph.D at the German University in Prague in 1936 under the direction of Philipp Frank he went to work with Einstein, as his research assistant, at the Institute for Advanced Study between 1936 and 1941. In 1942, Bergmann published the first textbook on General relativity, Introduction to the Theory of Relativity, with a foreword by Einstein. The second edition of this book was published by Dover Publications in 1976. His other textbooks were:
The Riddle of Gravitation
Basic Theories of Physics
He also co-wrote Albert Einstein: His Influence on Physics, Philosophy and Politics, together with Peter C. Aichelburg and Roman Ulrich Sexl.
Bergmann was a professor at Syracuse University from 1947 to 1982 and at New York University. He was posthumously awarded the first Einstein Prize in 2003. His doctoral students include Joel Lebowitz and Ranier Sachs.