Hi. I bought Messiah's "Quantum Mechanics" because it was at an excelent price from Dover. But, even though it was considered a Bible of quantum mechanics until recently, people consider it outdated now. Is it no longer comprehensive? I intend to read on relativistic quantum mechanics and quantum field theory from other books anyway. So, what are the handicaps of using this book to go deeper into QM? And if you only had Messiah's QM, would you pay more to get your recomended book? Thanks.