In 1901 Barbara married the historian, John Lawrence Hammond. Over the years they wrote a series of important books together on working class history including the trilogy: The Village Labourer (1911), The Town Labourer (1917) and The Skilled Labourer (1919). This was followed by The Age of the Chartists (1930) and The Bleak Age (1934).
Although Liberals rather than Socialists, the Hammonds were attacked for promoting the traditional left-wing view that the industrial revolution created a great deal of social misery for the working classes. Other historians argued that the living standards of the workers actually improved during the early stages of industrial capitalism.
Other joint works by the Hammonds included Lord Shaftesbury (1923) and The Rise of Modern History (1925). Barbara Hammond died in 1961.