A mismatch of tales from both WW1 and the archives of the Special Air Police.

From the police files:

• The case of the black gauntlet - Biggles is brought into a movie cast as a technical advisor as the movie includes some war flying. One of the pilots os a German lady whose brother Biggles shot down during the war. The lady holds a grudge and tries to kill Biggles, but in her rage crashes and dies.
• The case of the mandarin's treasure chest - Biggles organizes an expedition on behalf of the British Museum to collect some ancient Chinese art which was left behind after the Communist revolution. On the way he has to avoid not only the Chinese army but a plague of locusts.
• The case of the lost souls - An old soldier reports ghostly noises in the air at night, and Biggles traces them to an illicit balloon pilot smuggling dogs from the Continent into the south of England.
• The case of the too successful company - Biggles is suspicious when he comes across a small airline that makes a profit despite hardly ever having a customer. Investigation reveals links with the underworld and a sophisticated smuggling operation.
• The case of the white lion - Biggles is sent to Africa after reports of a white lion scare away the locals who are tending an experimental herd of cattle which will break Britain's reliance on expensive South American beef.
• The case of the remarkable perfume - An explorer comes to Biggles with a complaint that a major discovery was about to be commercially exploited - in effect, stolen. Biggles and the explorer race the criminals to the spot.

[Thanks to Michael Angelico for the precis]

From the WW1 archives:

• Biggles, then and now - a forward to these war stories written by Johns, explaining they're reprinted from The Camels are Coming. Apparently even at the time this book was published early titles were hard to come by.
• The white fokker
• The packet
• J-9982
• The balloonatics
• The blue devil
• Camouflage
• The ace of spades