To all intents and purposes this looks like a bonkers, entirely voluntary experiment, but perhaps it’s a form of extreme dopamine addiction. Either way, if Timberlake’s fall is inevitable — and without giving the story away it is a long, long descent into oblivion — his powers as both observer and writer make the journey utterly compelling. The sections on heroin are right up there with Edward St Aubyn’s Patrick Melrose novels, only funnier, more self-deprecating and counterintuitive. He’s brutally honest and unflinching in his self-appraisal. I lost count of the number of times he refers to himself as an asshole.