Several physical quantities in b-physics can be computed with the same  
theoretical method, the Heavy Quark Expansion. The first application 
which I discuss is the prediction of the lifetime differences among 
b-flavored hadrons. Then I move to the width differences in the B_s and  
B_d systems and the CP asymmetries in flavor-specific B_d and B_s
decays. These quantities are sensitive to physics beyond the Standard
Model and I discuss a GUT-inspired SUSY scenario as an example.