Jasper Dean is a motherless Australian teenager with a depressive father who takes him to lap-dancing clubs and declares: "Jasper, do me a favour. Pretend you're an orphan." In a naive desire for social improvement, Jasper installs a suggestions box outside the town hall, which rapidly fills with anonymous accusations and transforms a community rated the least attractive place to live in New South Wales into the most paranoid as well. Steve Toltz's big, boisterous debut goes off on so many tangents it's hard to remember where it was heading in the first place, but it just about hangs together through an inspired stream of bleakly comic observations, such as the moment Jasper comes to understand that his father "wasn't just a sceptic who doesn't believe in a sixth sense, but an über-sceptic who wouldn't trust or believe in the other five either". Jasper's first crush, on a lanky redhead he calls the Towering Inferno, is exquisitely done: "One day I stole her pencil case and kissed every last biro. I know how that sounds, but it was a very intimate afternoon, just me and the pens."

Five down, one to go. I'm slowly making my way through last year's Booker shortlist and, unless Sebastian Barry's The Secret Scripture proves to be invincible, this extraordinary Australian debut novel about, well, everything really - families, crime, celebrity, philosophy, religion, sport, relationships, travel and above all the search for identity - will have been my winning choice. To give any of the plot away would spoil the surprises, and it's full of wonderful surprises. The story is told alternately by Martin Dean - paranoid, intellectually brilliant, dysfunctional, achingly funny wannabe philosopher from a hick town voted the most boring in Australia - and his son Jasper, ditto. The frenetic action - prison revolts, serial killing, bush fires, exploding river barges carrying guns/drugs - swerves wildly between Poland, China, Australia, France and Thailand. Toltz's wit is as good as Clive James's, though maybe darker, and he can be lyrical, too: "the rhythms of the universe were perceptible in the way the boats were nodding at me." Brilliantly read by both actors to make you mourn as much as laugh, this David Copperfield Down Under on speed with son is an epic in every sense, including length. But don't be tempted, even if there is one, to get an abridged version. Every macabre detail, every chaotic incident, every wisecrack is an essential fraction of the whole. Heartfelt thanks to Whole Story Audio for getting this and half the other 2008 Booker shortlist out so quickly. To cut a single sentence would be criminal.