Len Deighton's Only When I Larf is a late 1960s British comic thriller describing the activities of a team of three confidence tricksters led by Silas Lowther (late 40s), his girlfriend Liz Mason (late 20s) and wannabe apprentice and Liz-worshipper Bob (early 20s). It was published in 1968 by Michael Joseph and in paperback by Sphere. It is currently (2012) printed by Harper in the UK.
The novel interleaves first-person narratives from Bob (76 pages in 7 chapters), Liz (78 pages in 6 chapters) and Silas (88 pages in 5 chapters). Their increasingly contradictory descriptions of shared experiences contribute to the humour. This unreliable narration adds to the atmosphere around deceiving "the marks", but the characters' different perspectives on their mutual relationship (interspersed with Silas's day-dreams of a dishonourable wartime incident) look more like self-deception and often add a poignant note. The title is explained in a variety of unlikely anecdotes where in each case a critically injured third party bravely replies this when asked "Does it hurt?"