This book presents a variety of techniques for tackling phenomena that are not amenable to the conventional approach based
on the concept of probabilities. The methods described rely on the use of path integration, thermal Green functions, time-temperature
propagators, Liouville operators, second quantization, and field correlators at finite density and temperature. Also exploring
the statistical mechanics of unstable quantum systems, the book is intended as a supplementary or reference text for use in
one-semester graduate courses on Quantum Mechanics, Thermodynamics, Electromagnetism, and Mathematical Methods in Physics.