Semi-classical analysis has become a mathematical tool for dealing with a variety of asymptotic problems. This book provides a systematic and extremely useful presentation of the theory in its traditional setting motivated by quantum mechanics. Both the standard C8 pseudodifferential calculus and the analytic microlocal analysis are developed, while the author replaces the delicate local theory with a more straightforward global theory. The only prerequisite required is a basic knowledge of the theory of distributions.
Contains some very nice explanations (particularly, its point of view on the frequency set and microlocalization) which more clearly expose some of the physical motivation behind these ideas than I have seen elsewhere.