This archive includes diary entries from January 1, 1912-July 12, 1972. Excerpts from earlier entries can be found in bound volumes of the "Lewis Family Papers," which Warren edited after retiring from a career in the Royal Army Service Corps in 1930. Volumes XIII-XVI show a listing of "contents" which Warren included on the cover pages of the volumes, but this practice was discontinued in later volumes. Warren also tended to number the pages of his diaries; both Warren's page count and the actual page count are given where the actual page count differs from Warren's numbering system.  Researchers may note that Warren often began a new volume of the diary with a quotation from literature or the Bible, and that he included original artwork, photographs and newspaper clippings in his diary, the latter two especially concentrated in later volumes.

Also included at the end of the archive are the seven 'Travel Journals' that Warren kept while vacationing in England and Ireland.