This is probably the "bible" of Statistical inference. However, from a students point of view it is, in my opinion, worth little more than the heat you can get from burning it. This text seems to be written by professors for professors with professors in mind. The book is extremely terse and the author bothers little in helping the student understand the subtleties of the arguments in proofs and examples, many of which are hard to follow, are extremely subtle, terse, and assume you have a very excellent knowledge of what has been written in earlier chapters. So unless you have acquired and encyclopedic knowledge of the earlier parts of the book and the numbering of Theorems and examples you will find yourself looking backwards and forwards to find what example or theorem 1.2.3.4, which you may have studied months ago, said.
The author only grudgingly and occasionally provides the poor reader with hints as to how to get from one step in an agreement to the next. Worse still some of the proofs are not clearly delineated as such and you have to be extremely alert to work out how some of the theorems are arrived at. In some cases the proof is given in un-delineated text before the statement of the proof causing considerable confusion.
The typography is completely unhelpful (the first edition was better) and a dyslexic's nightmare. All of the examples are quite abstract.
The author indulges in the irritating and unhelpful practice of leaving numerous aspects "as an exercise" or as one of the numerous exercises in the book of which there are a large number. A cardinal sin in my opinion. These exercise are also extremely subtle in places. The is an on line solutions manual for the exercises, however, in the style of the book these are extremely terse and hard to follow.
The first half of the book contains a treatment of probability. This contains a superficial treatment of Boreal fields which is completely unsatisfactory and really should have been left out. The second half a treatment of inference proper.
The author seems to have forgotten that the purpose of a text book is to communicate with the reader and help them understand. This book makes the process of understanding statistical inference, which is not easy in the first place, even harder as you have to decode his style and method of presentation. This may well be a bible of Statistical Inference, but, you will have to learn the Statistical equivalent of ancient Greek to understand it.
You may conclude that I do not like this book, and you would be right. The frightening thing is that there appears to be no alternative.