One of the first places to look for details of officers serving in the British Army are the various Army Lists that have been published in some form or another since Nathan Brooks produced the first one in 1684. After Brooks produced his list, many years elapsed before the Government published the first official list of officers. Some came out every year, whilst others appeared each month or every 3 months. Army Lists are not only useful in determining an officer's regiment or basic service details.
Locations are a case in point.
They were first introduced in Hart's Lists in 1840, and the idea was followed up in the Official Lists. During the Great War the locations of units were omitted from the Official Lists, but they were then re-introduced after the war had ended, only to be omitted again for the Second World War. Type of Commission Part II contains an alphabetical listing of all retired officers, and a new edition is produced every three years with supplements issued for the intervening years. There is also a Part III to the Army List which is only for internal use, and not available to the public. The most useful and commonly found unofficial Army List was produced by Lieutenant H G Hart of the 49th Regiment of Foot in 1840, and annually thereafter until 1915.