What has by convention been called 'John Lightfoot's journal' is in fact a four-volume series of journals, the first of which has never been published. The journals are presented here in their entirety for the first time. John Lightfoot's journals cover a period in the author's life when he was a member of the famous 'assembly of divines' meeting in Westminster Abbey. The Westminster assembly (1643-1653) was comprised of approximately thirty members of parliament and 120 ministers. By the outbreak of the war in England in 1642, a majority in the Long Parliament had come to see it as its duty to renovate the Church of England, both bringing it into line with a more biblical code and up to date with the best Reformed Churches. Lightfoot's personal diary is of critical importance to assembly history because his meticulous little volumes supply the only account of the assembly's activities for sessions 1-44, and the only fulsome account for sessions 120-154, where the assembly's own minutes are missing. For the sessions where the assembly's minutes are extant, Lightfoot offers another set of eyes, often supplying additional information and a perspective differing from the assembly's own scribe. These sessions record the gathering's opening ceremonies, surprising fractious debates over the Thirty-nine Articles, and predictably heated conflicts between Episcopalians, Presbyterians, and Congregationalists over church governance. Lightfoot describes riots outside parliament, names meeting places for MPs and assembly members in London, and attempts to explain assembly dynamics in a way that The Minutes and Papers of the assembly do not. The four-volume journal ends abruptly after eighteen months, in December 1644. The body of this volume contains the full text of Lightfoot's surviving journals, accompanied by interpretive introductions for each session and editorial notation throughout. The introduction sets in context the author's life prior to and during the Westminster assembly and discusses the careful composition, potential audience, and checkered transmission of the journals.