Written by a well-known professor of physiology at McGill University, this text presents an informative exploration of the basis of the Second Law of Thermodynamics, detailing the fundamental dynamic properties behind the construction of statistical mechanics. Geared toward physicists and applied mathematicians with an interest in the foundations of statistical mechanics, it is suitable for advanced undergraduate and graduate courses. Unabridged republication of the edition published by Springer-Verlag, New York, 1992.