This volume provides transcripts of returns of the 1851 Census of Religious Worship for the geographical counties of Cambridgeshire and Huntingdonshire, and notes patrons of Anglican livings, dedications of parish churches, references to Venn's Alumni Cantabrigienses or Foster's Alumni Oxonienses for Anglican clergy, and any other livings that they held, dissenting ministers' occupations from the relevant county directories, and parishes' populations in 1851. Tables for each registration district list numbers of churches and returns, and total numbers of sittings, and morning, afternoon and evening average attendance of congregations and scholars for each denomination, and for each county by denomination and registration district. This is the eighteenth volume of returns for (so far almost entirely rural) counties to be published since 1975. David Thompson first wrote about the Census in 1978, so his introduction represents mature reflection on the debates since Kenneth Inglis's article ‘Patterns of religious worship in 1851’ (this Journal xi [1960], 74–86) about how the returns may be read to assess the numerical strength of denominations in terms of church attendance. Thompson's judicious introductory review and evaluation of this literature should be essential reading for all future researchers on the Census. His excellent detailed discussion of the Church and nonconformity and the relative strengths of denominations in the counties, informed by knowledge of their social and economic context, should also provide a model for future editors of such volumes in providing a broader assessment of the significance and implications of the Census returns for understanding nineteenth-century English rural religion.