If you didn't know, this book is hard. I am a first year engineering student, and I felt lost through most of it. I gather it was intended for full-fledged physicists, but I was intrigued to read it anyway because of a philosophical thread running through the work. But beware--get ready for some Immanuel Kant and Einstein in only the introduction. This book is as much about the physics of time as the philosophy concerning subjectivity of time. Even though I didn't understand a lot of the probability or almost any of the quantum mechanics math, I still got some pleasure out of some of the more bizzare conclusions of the book. Did you know that for an isolated system (one not interacting with any others), time can't be said to have any direction? Furthermore, time as we know it is just a statistic. Another interesting fact is that on the quantum mechanical level, there is no such thing as time! If these things intrigue you (and you know what a double Riemann sum is) go for this book. Otherwise, be very afraid...

It is a beautiful but exterememly difficult book. It covers the concept of time and direction of time from the beginning up to current thinking. Author, being one of the founding fathers of philosophical quantum theory first introduces a good understanding of Thermodaynamics and Statiastical Physics and defines the order of events to lead into statistical definition of arrow of time. A lot of difficult concepts from Classsical Statistical Physics, Probability Theory, Relativity and Mathematical Logic as well as a good understanding of Quantum Physics is assumed to be in the bag of the reader, after all this book is not a Popular Science book. Although the author claims that knowledge of derivations of the formulas used are not critical to understand this study yet time to time the language and logic becames exteremely difficult. This is a must read book in this subject, may be many times or time and time over after increasing the understanding in other subjects that only tools in this book.

H.Reichenbach is undoubtly one of the most remarkable scientists that the world has ever witnessed. The interested mind is to be very strongly urged to read the book 'The direction of time' by him. Time is an essential concept to every physics student, as without it nature would be meaningless, and therefore the study of nature would be an empty pursuit. Whenever we wish to understand why we are in the 'world', say rather than in the planet MARS we have to understand thoroughly what actually happenned in the past, beginning from The Big Bang, that is, from the beginning of time. The book gives us a clear understanding into this inquiry ('TIME') developing both classical and quantum mechanical content of the concept of time starting from the first principles. The book carefully clarifies many confusing conceptions about time. For instance, the author clearly explains the contradictions lying in the famous Zeno's paradox which attemts to prove that time does not exist, in such a way that the physics student is now much more confident with such essential concepts as displacement and velocity. Also in the book, another essential concept of statistical physics ENTROPY is developed in a very systematic way and through this concept the direction of time is decisively established. Moreover, the issue of DETERMINACY or INDETERMINACY , an issue which is simply ignored in the text books or mentioned briefly in a few sentences as if it is self-evident and therefore does not need further elaboration, is discussed in depth, so both theoretical and experimental physicists have now a strong ground in arguing their proposals. I, as a physicist of 18 years of university lecturing experience, strongly recommend it to every single physics student or actually every single mind (student or not) who cares about the future, and who needs a decisive explanation (justification) for their potential steps to save (before being too late) our home THE WORLD WHICH WE NOW LIVE IN, only home only home and only home for us and for our childeren including of course our organic bodies, the animals and the plants. The direction of time and equally of The ENTROPY are the key concepts to understand what technology actually is, and to understand why it is inevitable to face more and more polluted environment as technology advances.