These notes contain material from lectures in two courses PHYS 303 and 455 at UBC. Sections 1-7 largely presents material given fall 1996. That year I went on to present the theory of Bose Einstein condensation and superfluidity following closely the discussion of a book that I co-authored with Michael Plischke at Simon Eraser University[1]. Since this material is in print I do not reproduce it here. Instead I have added a discussion of phase transitions from PHYS 455 some years earlier. Some of that material is also incorporated in the book mentioned above, but the emphasis is quite different. I have also added to section 2 some subsections on the Weibull distribution and on scale free distributions ("Pareto tail").