Sir Claud Amory’s revolutionary new formula for a powerful explosive is stolen. Locking his house-guests in the library, Sir Claud switches off the lights to allow the thief to replace the formula, no questions asked. When the lights come on, he is dead, and Hercule Poirot and Captain Hastings have to unravel a tangle of family feuds, old flames and suspicious foreigners to find the killer and prevent a global catastrophe. "Black Coffee" was Agatha Christie’s first playscript, originally performed in 1930 and made into a now rarely-seen film the following year. Combining her typically beguiling plot and sparkling dialogue with his own faithful narrative, Charles Osborne’s novelisation is "A worthy addition to the Christie canon".