This study presents the action and variational principles through which are developed such diverse topics in physics as classical mechanics, classical electrodynamics, special and general theories of relativity, and quantum mechanics.

The problem of minima and maxima
the calculus of variations
the principles of least action - Hamilton's principle
the action in classical electrodynamics
the action principle in continuous systems and fields
tensors in curved space-time
the action in general relativity
the action-at-a-distance
the action in quantum mechanics.