The papers nearly all relate to Russia and mainly consist of typescripts and offprints of Wilcox's published articles particularly from Fortnightly review including for example offcuts by Wilcox on Kerensky and Korniloff and Kerensky's responses (Fortnightly review September-December 1918).
There is some correspondence including a Russia related letter from A.I. Guchov to Wilcox in 1935, on the death of Guchov's brother [in Russian], letters from Irene Ward, 1942 and letters from E.C. Bentley to Wilcox written from the Daily News and later The Daily Telegraph offices, 1908-1923. E.C. Bentley was the author of Trent's last case and the inventor of the clerihew and he remained in contact with Wilcox for many years, although there are no extant letters later than 1923.
The collection includes a number of rare pamphlets, including B.V. Savinkov, Za rodinu i svobodu, Warsaw, 1920.
The papers include photographs relating to his time in Russia as well as personal and family photographs and personal and family correspondence, bills and receipts etc. relating to the last few years of his life spent in Newcastle upon Tyne whilst living at the Gordon and later, Cairns Hotel.