The collection consists of three volumes of correspondence, both sent and received, concerning Simonis's literary, wartime, and charitable activities. Letters span the years 1916-1919, and each volume is indexed, with correspondence filed alphabetically.

The first volume contains correspondence relating to his efforts to aid the British government in the dissemination of information to the public, the recruitment of workers for the war effort, and his appointment as Director of the Government Information Bureau. Correspondents include Neville Chamberlain, David Lloyd George, and Frances Stevenson.

The second volume also contains correspondence about various war work projects, and the third concerns Simonis's book The Street of Ink (1917), a history of Fleet Street, which he had begun as a series of newspaper articles. It includes correspondence with his publisher, Arthur Spurgeon of Cassell & Co., and letters from various newspaper editors, such as James Garvin, Lord Burnham, and Fisher Unwin, as well as congratulatory letters for the book.