H. Ohanian and R. Ruffini have admirably succeeded in writing a book primarily concerd with the physics of the gravitational field. Without diminishing importance to the mathematical apparatus underlaying the General Theory of Relativity, this book crearly, concisely and beautifully explains the ideas, concepts, experiments and some aspects of the history of the modern theory of Gravitation. It is a very different book from the ones already existing; it presents the theory in such a logical and elegant way, that it's impossible not to read the book with a feeling of respect and admiration for the theory. Just to mention an example; with the formalisim presented in chapter two, the authors derive Maxwell's equations in chapter three from nothing, or almost nothing, just requiring a linear theory invariant under Lorentz and gauge transformations!! The clarity of the presentation is so refined that when I finished this chapter I thought: "oh! Why I didn't think about it by myself?" This book is as good as the books by Misner et al, Schutz or Weimberg, but at the same time it's different from them. Definitely, this book is a good choice for students who are beginning with the topic, but I also recommend Ohanian and Ruffini's book to more advanced students looking for a better undesrtanding of the theory. Certainly, with this book I learnt and enjoied the beauty and elegance of the General Theory of Relativity in full.