Plymouth Brethren offers the first scholarly treatment of the Plymouth Brethren Christian Church (PBCC), one of the largest denominations within the Brethren movement that originated with John Nelson Darby and a 19th-century revival in the British Isles. The Brethren believed in restoring the purity of primitive Christianity. While some saw this dream in ecumenical terms, those who would eventually be called Exclusive Brethren came to believe that true Christians should separate themselves from the corruption of existing denominations, and break bread in their assemblies only with those sharing their interpretation of the Bible.

This book, based on both historical research and participant observation of contemporary communities, focuses on a case study of the Plymouth Brethren Christian Church, one of the largest groups of the Exclusive Brethren. Massimo Introvigne discusses their beliefs, daily life, international school system, and charitable activities. The book also examines the controversies surrounding their practice of strict separation from those who are not part of their community, and the accusations of cult-like behavior brought against the Brethren by the media and some former members.