In the early twentieth century, new mass media--popular newspapers, radio, film--exploded at the same time that millions of Britons received the vote in the franchise expansions of 1918 and 1928. The growing centrality of the commercial media to democratic life quickly became evident as organizations of all stripes saw its potential to reach new voters. The new media presented both an exciting opportunity and a significant challenge to the new Labour Party.

Laura Beers traces Labour's rise as a movement for working-class men to its transformation into a national party that won a...