Lecture notes on classical and quantum Olshanetsky-Perelomov systems for finite Coxeter groups, the rational quantum Calogero-Moser system, complex reflection groups, parabolic subgroups, Olshanetsky-Perelomov operators, Dunkl operators, uniqueness of the operators Lj, classical Dunkl operators, Olshanetsky-Perelomov Hamiltonians, and Rees algebras.