Biggles Works it Out. A Story of Air Detective-Inspector Bigglesworth and his Comrades of the Air Police - Captain W.E. Johns 1951 - Hodder & Stoughton, London - First Edition Biggles get suspicious over a series of robberies that could only have been managed with air support. Suspecting a single gang is behind them all he seeks to infiltrate and then capture the gang in action.

The adventure wanders from England to Australia to Monte Carlo, before a climax in the gang's hideout in the African desert. With thanks to Bertie (going undercover) and Marcel (his first case with Biggles) the gang is captured and/or killed trying to escape.

With eight wonderful full page tinted illustrations by Stead.
  First Edition Points - Copyright page with statement ‘First printed 1951’ (which changed to ‘Oct 1951’ for the second impression). Rear flap of dust jacket lists up to Biggles Works it Out (second impression lists up to Biggles Takes the Case).

Reference - YABS. Biggles online 40.1.

pp. 192. In publisher’s red cloth, lettered in black to spine, front board with vignette and lettering in black. Dust jacket priced 7/6 net to lower corner of front flap.
  Condition: Near fine, owners name to front pastedown, some spotting to edges in bright near fine jacket with a little soiling to rear panel.   Ref: 105555   Price: HK$ 1,600