Variational principles have proven to be surprisingly fertile. For
example, Fermat used variational methods to demonstrate that light
follows the fastest route from one point to another, an idea which came
to be a cornerstone of geometrical optics. This book explains
variational principles and charts their use throughout modern physics.
It examines the analytical mechanics of Lagrange and Hamilton, the basic
tools of any physicist. The book also offers simple but rich first
impressions of Einstein's General Relativity, Feynman's Quantum
Mechanics, and more that reveal amazing interconnections between various
fields of physics.