Some aspects of the physics of many-body systems arbitrarily away from equilibrium, mainly the characterization and irreversible evolution of their macroscopic state, are considered. The present status of phenomenological irreversible thermodynamics is described. An approach for building a statistical thermodynamics - dubbed Informational-Statistical-Thermodynamics - based on a non-equilibrium statistical ensemble formalism is presented. The formalism can be considered as encompassed within the scope of the so-called Predictive Statistical Mechanics, in which the predictability of future states in terms of the knowledge of present and past states, and the question of historicity in the case of systems with complex behaviour, is its main characteristic. The book is recommended for researchers in the area of non-equilibrium statistical mechanics and thermodynamics, as well as a textbook for advanced courses for graduate students in the area of condensed matter physics.Thermodynamics is considered to be an offshoot of the Industrial Revo? lution that began in England in the second half of the 18th Century and from there spread to other parts of the world. The word thermodynamics is derived from the Greek therme (meaning heat) and dynamis (meaning force). As well known, the origins of thermodynamics are founded in the early 19th century in the study of the motive power of heat; that is, the capability of hot bodies to produce mechanical work. However, there are of course precursors to these ideas: Temperature is probably the earliest thermodynamic concept to attain operational status (early in the 17th century with Galileo). The science of calorimetry beginning in the late 18th century (contemporary with the beginning of the Indus? trial Revolution) led to the establishment of the caloric theory of heat [5]. Clausius in the second half of the 19th century established Thermody? namics as a clearly defined science. The connection of Thermodynamics with Mechanics is first l