The Building Society Promise explores the accessibility of the early building society movement to working-class households before the Second World War. The study examines the historical records of building societies which existed in the past and reconstructs their mortgage portfolios to investigate the kinds of people that were buying houses with the help of building society finance during this period. Antoninus Samy shows how the accessibility ofdifferent building societies primarily depended upon the how individual societies were designed to do business, which in turn also affected their efficiency and stability. Societies that were small and highlylocalized (or large societies that had agency networks that were closely knit with the communities they served) were more likely to be accessible, efficient and stable, than larger societies that operated no differently than impersonal corporate banks.