Meant as a text in an advanced undergraduate or beginning graduate course in mathematics, computer science, or philosophy, this two-volume work is written in a user-friendly conversational lecture style that makes it equally effective for self-study or class use. Volume II, on formal (ZFC) set theory, incorporates a self-contained 'chapter 0' on proof techniques based on formal logic, in the style of Bourbaki. This provides the reader with a solid foundation in set theory, while the inclusion of topics such as absoluteness, relative consistency results, two expositions of Godel's constructible universe, numerous ways of viewing recursion, and a chapter on Cohen forcing, will usher the advanced reader to the doorstep of the research literature.