The Shadow on the Glass

Mr Satterthwaite attends a party at a house where all the guests are gossiping about the ghostly figure in the upstairs window: a cavalier, murdered by his wife's lover. But when a real murder takes place it is only through Satterthwaite's patient and observing nature that the crime can be solved. With the appearance of Mr Quin, Satterthwaite knows the cause of death is often love.

Based on the character of Harlequin from the Italian Commedia dell'arte, Agatha Christie indulges in her fascination with the supernatural as well as her love of theatre and performance. This story also contains a reference to Greenway House in Devon, a house Agatha Christie had long admired and finally bought as her holiday home in 1938. She described it as "the loveliest place in the world" and it is now managed by the National Trust and visitors can access the entire grounds including the boathouse, the battery and the quay.

The story was first published in book form in the collection The Mysterious Mr Quin, published by Collins in 1930. The collection was dedicated to its eponymous hero and is the only book of Agatha Christie's to be dedicated to a fictional character.

It has never been adapted.