Humanity has been estranged from the Earth, which, along with Jupiter, has been claimed by the mysterious and seemingly all-powerful alien Invaders. However, civilization has burgeoned and diversified on Luna and the other worlds, moons, and planetoids of the Solar System, which now bustles with commerce and a plethora of societies each seeking their own ideal. Any injury short of brain damage can be rapidly healed; longevity and perhaps even immortality is taken for granted; sex changes are routine. For most, but not all, it is close to Utopia.

Sparky Valentine is one of those inhabiting the interstices of Utopia. Once the child star of Luna's favourite children's TV show, Sparky and his Gang, he is now a jobbing actor and grifter touring the outer reaches of the Solar System with his dog, Toby, an omnicompetent trunk (the Pantechnicon Mark III, which functions much as the Luggage does in Terry Pratchett's Discworld series), implants in his face and body which allow him to change his appearance at will, and Elwood P. Dowd, a manifestation of his conscience that only he can see. Valentine is an engagingly amoral rogue, a survivor who lives only for the next performance or the next con, and at first the story is a discursive picaresque, packed with banter, nice bits of business, shameless parodies and cheerfully reworked clichés. But then the real plot begins to bite, and Valentine's mask begins to slip.

While on Pluto, he learns of a forthcoming production of "King Lear" on Luna -- the Golden Globe, the centre of human civilization -- by the greatest director of his time, who also happens to be his friend and former collaborator. After shamelessly hustling for the part, he is told that it is his providing he can get there in time; at the same time, he discovers that someone has set an assassin from the implacable Charonese mafia on his tail, in revenge for one of his half-forgotten little crimes. And so the chase is on, and we begin to learn of Valentine's strange education and damaged childhood at the hands of his strict and tyrannically autodidact father, and of the tragedy of his escape and the reason why he's spent so long on the run, a story which only fully unravels in a showpiece trial.

It's a relaxed, playful, virtuoso performance, packed with incidents and wonders as casually deployed as scarves from a magician's hat, which vividly evokes a Solar System where all history is, of necessity, as postmodern and hyperreal as Disneyland (the pocket habitats which recreate bits of lost Earth are themselves called disneylands). It is a performance which never falters as, told in Valentine's arch, knowing and perfectly realized voice, the narrative moves from comedy to tragedy.

As in Steel Beach, there are overt homages to Heinlein: there's the semi-secret enclave of liberationist technologically elite Heinleiners, of course; mini-lectures on everything from the impossibility of maintaining borders in space to the ideal judicial system; the little matter of Valentine's name; and more strongly, the character of Valentine's father, the embodiment of all the autodidact fathers in Heinlein's fictions, and so, by default, of Heinlein himself. Strongest is the sense of Varley having fun, playing off the corners of his densely imagined world, drawing the reader into a plot more tangled than it first seems, and tying up every loose end with consummate skill. The Golden Globe may not be as innovative as his early work -- it would be unfair to expect that -- but it's still one of the best SF novels of this year.