Preface. Introduction. 1: Dirac Observables and psi do-s. 1.0 Introduction. 1.1 Some Special Distributions. 1.2. Strictly Classical Pseudodifferential Operators. 1.3. Ellipticity and Parametrix Construction. 1.4. L2-Boundedness and Weighted Sobolev Spaces 1.5. The Parametrix Method for Solving ODE-s 1.6. More on General psi do-Results. 2: Why Should Observables be Pseudodifferential? 2.0. Introduction. 2.1. Smoothness of Lie Group Action on psi do-s...