Showalter identifies clusters of syndromes, or mini-epidemics, which she suggests represent late-twentieth century manifestations of the entity which was called hysteria in nineteenth century western culture. Opening with the history of psychiatry's involvement in hysteria in the time of Charcot and Freud, she traces the replacement of hysteria or conversion reaction by modern hysterical analogues such as: chronic fatigue syndrome, recovered memory, Gulf War syndrome, multiple personality syndrome, satanic ritual abuse, and alien abduction.

In separate chapters she examines each of these entities--how it presents, how it fits into her theory of mass hysteria as a cultural response to the millennium, and how it is being handled by health care professionals. Showalter contends that "Redefining hysteria as a universal human response to emotional conflict is a better course than evading, denying, or projecting its realities." (p. 17)