The art historian, John Rewald first became involved with the Pissarro family in 1932 when he met Rodo in Paris while preparing his Cezanne thesis at the Sorbonne. Encouraged by Rodo, Rewald introduced himself to Lucien and his family during one of his frequent visits to London. A strong friendship developed and Rewald was entrusted with the task of editing and publishing Camille's letters to Lucien. Rewald never failed to visit the Pissarros when he was in London and corresponded regularly when he was not; he was regarded as one of the family at The Brook.
(see W.S. Meadmore, Lucien Pissarro, London, 1962, p.211).