With the rising importance of cosmology has come an increasing flood of textbooks on modern cosmology. While I have not surveyed all the textbooks out there, many of those I have looked at suffered from serious problems. Recently, I had the opportunity of looking at Slava Mukhanov's new book on cosmology and I was so struck by its excellence that I am moved to post a review on Amazon, something I am not in the habit of doing. The bottom line is that I heartily recommend to any student or physicist serious about mastering modern cosmology. Mukhanov is one of the earliest pioneers in inflationary cosmology and a towering figure over the whole field, particularly when it comes to actual calculation, as compared to mere talk, of the density fluctuation spectrum.
Different people have different criteria for an outstanding textbook. I like a textbook to slice away all the obscure and unnecessary formalism shrouding the subject and to get through to the underlying concepts and the important physical ideas. So, dear reader, if you love heavy dry formalism that does not help you understand physics, then this book is not for you. (An aside: from a cursory glance at some of the reviews of physics books posted on Amazon I was amazed by the number of readers, apparently misinformed and misguided, more interested in mathematics and formalism than in understanding physics.)
There is a whole spectrum of books on cosmology. There are the giant compendia of every imaginable topic, but with almost nothing really derived, such as the book by Peacock. Then there are those books notorious for the amount of hype and hot air they blow. Such books apparently really appeal to people who want to "grasp" cosmology without doing any work; they could just read the hype and "be happy." On the opposite end of the spectrum is the book by Scott Dodelson, which is full of nitty gritty, the real stuff that you need to do detailed cosmic microwave background calculations, and which for that reason I highly recommend to students wanting to become professional cosmologists.
I have not read Mukhanov's book in its entirety. I read the parts on inflation and looked at his treatment of density perturbations. I really like his discussion of inflation, which carries the stamp of authority and deep understanding associated with a master who invented the subject. He cuts to the essential physics of the different approaches and wisely refrains from presenting the one thousand and one inflationary scenarios that have flooded (some would say, polluted) the literature. When he comes to density perturbations, he does it as simply as possible, and most importantly, correctly. Students should be aware of the fact that many of the well-known papers on the subject contain errors, as Mukhanov points out in a very helpful and biting footnote.
I recommend this book enthusiastically to all those serious about modern cosmology.