Defining "yesterday's radicals" as 19th-century Anglican Broad Churchmen and Unitarians, this text shows how they influenced each other over issues such as biblical criticism and inspiration. It shows the affinity between them, as they tried to grapple with the problems of their day. The author takes the reader through the ramifications and complexities of biblical criticism, and discusses the answers given to the problems of biblical inspiration, miracles and other subjects. He shows how Unitarians and Broad Churchmen influenced each other, and reveals that much which is now taken for granted in enlightened theological circles was developed by yesterday's radicals. The study was awarded the Earl Morse Wilbur Prize for Historical Research.