The Magicians describes the experiences of the author, a sociologist-anthropologist, who spent six months as a participant observer in a black magic group. In the book, this California-based national secret magical and religious group is called the "Church of Hu", though it has become nationally known as the Temple of Set. Members of the group, mostly from the well-educated middle class, consider themselves an elect and seek to develop themselves magically to achieve power.

The Magicians looks at the group's beliefs, attitudes, and values, and shows how its focus on power and magic affects the members in everyday life. The book also discusses the dynamics involved in the search for power and considers the danger to society of groups using black magic to achieve power.