This book is an in-depth exploration of the Popular Front and United Front campaigns in Britain in the late 1930s. Dr Blaazer aims to dispel the myth that these campaigns can be understood largely as a ruse engineered by the Communists into which non-Communists were blindly drawn. Instead he searches for the idea of 'progressive unity' in earlier episodes in the history of the British progressive tradition. By re-assessing the significance of these episodes, and by reconsidering the role of seminal progressive thinkers, he shows that the relationships between liberals and socialists, reformists and revolutionaries, had long been both intimate and fluid. Indeed, the reasons and assumptions behind individual decisions to support the struggle for progressive unity show that the Popular Front was a reasoned and culturally familiar response to a major political crisis.