I am reading Steven Weinberg's quantum field theory textbook these days. I attempted to read this book a long time ago to teach myself some quantum field theory but it didn't work out. Now, I can read this book at quite a fast pace, because I know some quantum field theory. As somebody said, this is not a good book to start learning quantum field theory, and I agree to this point of view. In the preface of this book, Weinberg says that he wrote this book to explain why the quantum field theory is as it is and why there is no other choice. I believe that it's worthwhile to read this book. Who knows? Probably, I will end up reading all the three volumes of this book, even though that may take a lot of effort and time.