Sperry and Scofield are the two most significant figures in systemising and popularising the Dispensationalist belief's of J. N. Darby. Williams traces the development of dispensationalism as a cultural and theological critique on 19th century America and England and its influence on the current instinctive spiritual beliefs of America. He analyses the internal logic that dispensationalists attempt to apply to their theology and the notable changes that are taking place within it today.