Starting from the earlier notions of stationary action principles, these tutorial notes shows how Schwinger’s Quantum Action Principle descended from Dirac’s formulation, which independently led Feynman to his path-integral formulation…

Julian Schwinger was already the world’s leading nuclear theorist when he joined the Radiation Laboratory at MIT in 1943, at the ripe age of 25.

Classical Electrodynamics captures Schwinger’s inimitable lecturing style, in which everything flows inexorably from what has gone before.