The sinister, murky world of espionage is laid bare in this revised and updated edition of Philip Knightley's powerful book about spies and spying in the 20th century.

The author is cynical about the intelligence business, not least about its efficacy, and reveals the staggering extent to which such services have shaped, and even manipulated, the policies of governments.

Knightley reminds us that intelligence services have a vested interest in their own survival, so must constantly postulate some or other threat to the nation.

Since September 11, international terrorism has given intelligence a new lease of life.

ANTHONY LOOCH