Valley of Fear (Penguin Books)

The Penguin English Library Edition. The deadly hand of Professor Moriarty once more reaches out to commit a vile and ingenious crime, but a mole in Moriarty's criminal organization alerts Sherlock Holmes of the evil deed żeby means of a cipher...When Holmes and Watson arrive at a Sussex manor house they appear to be too late. The discovery of a body suggests that Moriarty's henchmen have been at their work. But there is much more to this tale of murder than at first meets the eye.