Sidney Southgate Pawling was a publisher and business manager.
JW met Pawling in 1890 when he became the business partner of the publisher William Heinemann. Aided by family money, Heinemann's publishing house had just commenced business. Pawling had formerly worked for Mudie's Circulating Library, then a major force in the book-publishing trade and thus he provided a steady hand for the day-to-day affairs of the Heinemann firm.
Whyte, Frederic, William Heinemann: A Memoir, London, 1928; de Montfort, P., 'Whistler and Heinemann: Adventures in Publishing in the 1890s,' The Whistler Review, vol. 2, 2003, pp. 64-73.