Immediately after graduation from Oxford in 1932, Hodgkin went to work in Bernal's laboratory in the Department of Mineralogy at Cambridge, where she remained until 1934. Bernal became and remained an important influence in her life - perhaps second only to Thomas. His fertile scientific mind suggested and encouraged ideas for research; his strongly leftwing political views chimed with hers, though she did not quite follow him (or, later, Thomas) into the Communist Party; their intimate personal relations changed after her marriage but they remained on terms of deep affection and respect. Hodgkin's long acquaintance with Bernal often led to requests for information or contributions to publications. After his death in 1971 she undertook two major commissions: the Biographical Memoir for the Royal Society, published in 1980, and a lecture 'Microcosm: the world as seen by John Desmond Bernal' delivered in Dublin, Oct. 1980 and published in Proceedings of the Royal Irish Academy, 1981.

In the course of her writing, Hodgkin accumulated considerable information, correspondence etc., which is at MS. Eng. c. 7947. After the appearance of the Royal Society Memoir, she was contacted by Professor Alan Mackay who had traced and arranged publication of Bernal's early (1923) paper 'The analytical theory of point systems'. Hodgkin had referred to this paper, then apparently lost, in her Memoir (pp.24-26). A copy of the recovered work is at MS. Eng. c. 7945/5. Bernal's manuscript draft of his autobiographical 'Microcosm', with a few annotations by him, and by Hodgkin, is at MS. Eng. c. 7946/2-7. A little correspondence is at MS. Eng. c. 7946/11-12.