On 26 June 1878, 30-year-old Mary Booth composed one of her regular letters to her husband, Charles, who was on one of his frequent forays to look after the family shipping and leather business in New York. She was at home in their London house, 6 Grenville Place, South Kensington, a generous stuccoed mansion, though sunless and prone to draughts. Mary's cousin Beatrice Potter, the future Beatrice Webb, dubbed it ‘dark, dull and stuffy and somewhat smelly’ – the Victorians had a lot of problems with drains. In the summer of 1878 Mary Booth was in Grenville Place, with her five-year-old daughter Antonia, and two sons, Thomas, aged four, and baby George, who was nine months old. Her husband Charles had been worried about her. She had been having palpitations and complaining of stress, some clearly caused by the death two years earlier of their little girl, Polly, whose birth and death from croup had occurred between the births of the two boys. So there was Mary, in her comfortable house, with a considerable number of servants, in constant communication with her liberal intellectual parents and a wide circle of relatives, friends and acquaintances who together made up ‘the intellectual aristocracy of London’, a husband much occupied with business affairs, and a great deal of house- and child- and servant-management work to do. There were gnawing subterranean questions about the singular purpose of her own life, but in her letter to Charles she reflected on what the two of them had already achieved together, and what might await them in the future: ‘At present there are only beginnings,’ she wrote, ‘a fair and promising opening of such a serious life of effort as we may hope to carry on to some perhaps not wholly satisfying; but still worthy and intelligent conclusion.’ They needed, she estimated, another ten or twelve years in which adequately to impress themselves on their children and their surroundings. This was an effort in which, ‘We need each other absolutely. We can't stir a step without each other.’

It was during the ensuing twelve years that Charles Booth's most publicly lauded achievement, the 17-volume Life and Labour of the People in London, was conceived, gestated and born. This was an endeavour that changed political thinking in Britain about poverty and the role of the state.