This is an exceptional book. Professor Cheng has gone to considerable length to keep the explanations and derivations very clear. I am particularly pleased with the discussion questions and problems with solutions.This is one of several books I have read to teach myself GR. It is by far the most understandable text. However, GR is a difficult topic and this book requires great concentration. (i have a PhD in physics.) If your background is not strong in linear algebra and differential equations, I suggest you start with a book by Peter Collier, "A Most Incomprehensible Thing" which is a self-study book aimed at a more general user. Collier's book provides a crash course in the necessary mathematics.