This series comprises squadron diaries containing a day-by-day account of the domestic and administrative activities of some of the Fleet Air Arm's front line and training squadrons, mainly from the World War 2 period but with some post-war diaries for training and RNVR squadrons.

Further diaries are held by the Fleet Air Arm Museum at Yeovilton, Somerset, along with some squadron"line books". Line books are a less formal record of a squadron's activities and mishaps, enlivened by photographs, cartoons etc.