The maps were mostly listed by Roger Hellyer in 1999/2000 and 2004. This listing was copied into Cambridge University Library's Archive catalogue in early 2019 at which point some maps (e.g. Popular edition one-inch maps of Scotland) which had not previously been listed were added, and subsequently further items have been listed. The KGM numbers (Maps KGM 4.10 ; Maps KGM 5.1, etc.) are derived from the series and map type numbers in Roger Hellyer's "Ordnance Survey small-scale maps : Indexes 1801-1998", published by David Archer in 1999. The number after the colon (:) is usually the sheet number ; the number after a forward slash (/) indicates the copy number (there may just be 1 copy or there may be more). Many of the maps have been backed on linen by Guy Messenger and/or have home-made covers. Many also have home-made slip cases of various sizes, made out of cardboard (sometimes recycled corn-flake cereal boxes) and tape or sticky-back plastic, or were stored in 'Grape Nut' cereal boxes (sometimes covered ; "Grape Nuts, crunchy wheat & malted barley breakfast cereal. Stays crunchy in milk") but only samples have been retained. Some other maps belonging to Guy Messenger have been added to the Map Department collections and are catalogued in the Library's online catalogue. Where Guy's non-series / non-Ordnance Survey maps duplicated CUL's holdings, the maps were not retained. A blog post about the project to list and re-box the collection can be found at https://specialcollections-blog.lib.cam.ac.uk/?p=18192 Documents created and curated by Guy Messenger can be found as part of the Charles Close Society Archives at CCSA_KGM.