This book originated in a graduate statistical mechanics course I taught at New York University in 1964. Interest in the Boltzmann equation was again
finding its way into physics after lying dormant for over half a century. The phrase "kinetic equation" was becoming part of the vocabulary of plasma,
reactor, and astrophysicists. In aerodynamics the formidable problem of the structure of a shock wave had long before forced investigators back to kinetic theory. Also at that time it was becoming apparent that a gap had developed between the material covered in a standard statistical mechanics course and the esoteric works on kinetic equations that had begun to appear in the literature. Thus I was motivated to include a few lectures on this topic in the course.