Edwin Thompson Jaynes (July 5, 1922 – April 30,[1] 1998) was the Wayman Crow Distinguished Professor of Physics at Washington University in St. Louis.

He wrote extensively on statistical mechanics and on foundations of probability and statistical inference, initiating in 1957 the maximum entropy interpretation of thermodynamics[2][3] as being a particular application of more general Bayesian/information theory techniques (although he argued this was already implicit in the works of Josiah Willard Gibbs).

Jaynes strongly promoted the interpretation of probability theory as an extension of logic.

In 1963, together with his doctoral student Fred Cummings, he modeled the evolution of a two-level atom in an electromagnetic field, in a fully quantized way.

This book, which he dedicated to Harold Jeffreys, was published posthumously in 2003 (from an incomplete manuscript that was edited by Larry Bretthorst).