The ODNB has biographies of both John Letts and his son Thomas. The former references F. Vivian, ed., Letts keep a diary: an exhibition of the history of diary keeping in Great Britain from 16th–20th century in commemoration of 175 years of diary publishing by Letts (1987) [exhibition catalogue, Mall Galleries, London, 28 Sept – 25 Oct 1987], and W. H. Beable, "Charles Letts's diaries", Romance of great businesses, 2 (1926), 211–20. The latter has a reference to Charles Letts & Co., The romance of the business of a diary publisher (1949). --Hegvald (talk) 18:46, 24 May 2009 (UTC)Reply
