The asymmetry of natural phenomena under time reversal isstriking. Here Zehinvestigates the most important classesof physical phenomena that characterize the arrow of time,discussing their interrelations as well as striving touncover a cosmological common root of the phenomena, such asthe time-independent wave function of the universe. Thedescription of irreversible phenomena is shown to befundamentally "e;observer-related"e;. Both physicists andphilosophers of science who reviewed the first editionconsidered this book a magnificent survey, a concise,technically sophisticated, up-to-date discussion of thesubject, showing fine sensivity to some of the crucialphilosophicalsubtleties. This new and expanded edition willbe welcomed by both students and specialists.