A Sweet Obscurity, by Patrick Gale

Patrick Gale's novels have become progressively more difficult to précis; none more so than A Sweet Obscurity, his longest and most ambitious since The Facts of Life in 1995. Like its predecessor Rough Music, A Sweet Obscurity is set in Cornwall, where Gale now lives. It shares with that work a fascination with untypical relationships and families. Equally evident are the characteristic hairpin bends of storyline and Gale's disarmingly relaxed exposition of malice, incompetence and the human instincts of attraction and dislike. As in Rough Music, landscape plays a distinct role. Again one is reminded of Hardy – though also of interwar women novelists like Ivy Compton-Burnett and Rosamond Lehmann.

Lehmann's The Ballad and the Source was narrated by 10-year-old Rebecca, who described grown-up passions from a child's perspective. Gale's novel revolves around a heroine of similar age, Dido. Ever perverse, he bestows on Dido the maturity withheld from her non-biological "parents" Eliza (actually her aunt) and Giles. These have, in turn, separated.

Each becomes involved in a sequence of proliferating relationships. The angelic-looking Giles is seeing Julia, whom he likes but cannot love. He finally feels able to propose to her – not when she becomes pregnant, but when she pretends to have lost the child. Giles is disturbed by the sexual dreams he starts having about stepdaughter Dido. An innocently meant but arguably indecent photo he took of her develops an exceptional power over him and the novel. Meanwhile, the more straightforward Cornish farmer Pearce takes up with Eliza, just as her postponed academic career looks set to propel her from the farm that is his birthright and universe.

Lehmann and Compton-Burnett shocked their contemporaries with brutal accounts of then-taboo subjects like homosexuality, abortion and abusive parenting. Gale does likewise. Though the paedophile theme may seem modish, it remains daringly off-centre. Peripheral characters are typically well drawn – like the bisexual, amoral rake Villiers. He provocatively tells a dinner party he was "a filthy little boy", "gagging for it" aged 10. Otherwise Gale's players are pretty much all heterosexual, though unorthodox in taste. (There's the usual run of girls dressing like boys). An exception is the Elizabethan poet-composer Roger Trevescan, subject of Eliza's studies and early victim of a gay smear campaign.

Contemporary classical music features prominently, as Giles is a professional counter-tenor. Accounts of this tiny world include a hilarious account of a "transgressive" staging of Britten's Midsummer Night's Dream. The director "had toyed ... with the idea of naked boys, ones as near the illegal age as possible, but abandoned that since none could be found who were both willing to strip and able to sing treble."

The title of this 12th book by the prolific Gale (just 41 this year) could not be less apt. The commercial triumph of Rough Music leaves his name far from obscure – especially among his legions of female fans. If some readers found his earlier novels a little saccharine, A Sweet Obscurity provides a strong, even bitter corrective. This is arguably his most questioning, troublesome work. It amuses, startles and occasionally bewilders. A Sweet Obscurity is worth every minute of your time.

Richard Canning is writing a life of Ronald Firbank