Like many entries in the series it contains elements of farcical and surrealist humour, and does not follow the standard pattern of the Golden Age detective novel.

[3] In the Times Literary Supplement, reviewer Maurice Willson Disher described it as "an incoherent sandwich: alternate slabs of instruction and entertainment".

At the same time in London, equally intriguing reports arrive of a reputedly haunted eighteenth-century townhouse disappearing from Bloomsbury.

Before long Appleby is on a cargo ship heading for South America with his colleague Hudspith, who believes they are on the trail of white slavers.

He reveals himself as a man who is trying to conduct a vast series of experiments in the supernatural to try to corner the market in witchcraft and other unnatural phenomena.