In 1933, Hepworth co-founded the Unit One art movement with Nicholson and Paul Nash, the critic Herbert Read, and the architect Wells Coates. The movement sought to unite Surrealism and abstraction in British art. Hepworth also helped raise awareness of continental artists amongst the British public. In 1937, she designed the layout for "", a 300-page book that surveyed Constructivist artists and that was published in London and edited by Nicholson, Naum Gabo, and Leslie Martin. Hepworth, via Nicholson, birthed triplets in 1934: Rachel, Sarah, and Simon. For a woman of this period, the practicalities of dealing with multiple babies were intense. Hepworth, atypically, found a way to both take care of her children and continue producing her art. "A woman artist," she argued, "is not deprived by cooking and having children, nor by nursing children with measles (even in triplicate) – one is in fact nourished by this rich life, provided one always does some work each day; even a single half hour, so that the images grow in one's mind." Hepworth married Nicholson on 17 November 1938 at Hampstead Register Office in north London, following his divorce from his wife Winifred. Rachel and Simon also became artists. Hepworth, Nicholson and their children went to live in Cornwall at the outbreak of the Second World War in 1939. Hepworth lived in Trewyn Studios in St Ives from 1949 until her death in 1975. She said that "Finding Trewyn Studio was sort of magic. Here was a studio, a yard, and garden where I could work in open air and space." St Ives had become a refuge for many artists during the war. On 8 February 1949, Hepworth and Nicholson co-founded the Penwith Society of Arts at the Castle Inn; nineteen artists were founding members, including Peter Lanyon and Bernard Leach. Hepworth was also a skilled draughtsman. After her daughter Sarah was hospitalised in 1944, she struck up a close friendship with the surgeon Norman Capener. At Capener's invitation, she was invited to view surgical procedures and, between 1947–1949, she produced nearly eighty drawings of operating rooms in chalk, ink, and pencil. Hepworth was fascinated by the similarities between surgeons and artists, stating: "There is, it seems to me, a close affinity between the work and approach of both physicians and surgeons, and painters and sculptors."