James Meek's 2005 novel, The People's Act of Love, was critically acclaimed, shortlisted for the Man Booker prize and sold in 30 countries; in 2008 he published We Are Now Beginning Our Descent, which went on to win the Prince Maurice prize  I was a Man Booker judge that year and tried in vain to get it on the longlist. Yet McEwan- or Barnes-style fame has as yet eluded him, which is baffling. Here is a novelist writing fat, complex but readable novels that have something serious to say about the way we live now and the society we live in. Along with Philip Hensher, he is the nearest British fiction has to a John Irving.

There are two elements that characterise Meek's work: his use of humour and his range. The Heart Broke In opens with married TV producer and ex-rock star Ritchie Shepherd realising that the mobile phone he uses to call his teenage girlfriend has become lost in the long grass at the family home; a comic set piece follows as Ritchie tries to reclaim the phone from his children. Ritchie is a believably revolting type of middle-aged male; high-earning with a beautiful wife and home, throwing a young mistress into the mix, more because of his own sense of entitlement than lust.

One of the endearing qualities of Meek's writing is that he seems to despair of his own gender. Ritchie's sister Bec is everything her brother isn't: an idealistic scientist who has devoted her life to finding a vaccine against malaria, even going so far as to infect herself with a parasite that may blind her in the services of her quest. Meek's grasp of his research is superb: you really do believe that Bec is the kind of woman who is happier sleeping in the lab fully clothed than dating her wealthy newspaper editor boyfriend.

The boyfriend, Val Oatman, a deranged religious fanatic, is a less convincing character. When he leaves his job as a result of mental illness, he sets up a website called Moral Foundation that publishes allegations against well-known figures, unless they provide salacious details about someone else's failings. Oatman's desire for revenge against Bec after she refuses to marry him provides the narrative impulse behind the book. It's a plot device that is really just the excuse for a detailed examination of personal betrayal. When Ritchie's affair is revealed to the Moral Foundation, the odious Oatman offers him a choice  give me some dirt on your sister or I will expose you. How far will Ritchie go to save his own skin?

Meek's background as an acclaimed foreign correspondent feeds pleasingly into his fiction: he is as comfortable writing a scene set in the bush in Tanzania as he is writing one set in a London pub. Bec's strand of the narrative moves from the UK to Africa and back. Meanwhile, her worm of a brother sets out to redeem himself by making a film about the Irish republican executioner who tortured and killed their hero father, Captain Gregory Shepherd of the Special Boat Service, but Ritchie's every attempt to make himself feel better about his behaviour drags him deeper into a moral quagmire.

The biting wit and social satire that characterised We Are Now Beginning Our Descent manifests itself in this novel with an entertaining cast of minor characters. Bec and Ritchie's mother Stephanie is a vain sixtysomething, obsessed with endless health and beauty regimes. When she justifies this by saying she has no intention of dying young, her tactless daughter responds: "Mum, it's too late for you to die young."

The huge cast list diffuses the narrative drive somewhat but if there is a fault in this book, it's more to do with Meek's chosen form than his skill at executing it. The multiple-point-of-view novel can often seem a slow burn as character after character is introduced and each strand of the story set up. When part one ends with the dramatic development of Oatman's blackmail plot, it is quite annoying to be introduced to the back story of Alex, an old bandmate of Ritchie's. Alex will turn out to be one of the main characters  Bec's true love, in fact  but we don't know that at the time.

It's an occupational hazard of writing the fat narrative that the end result can sometimes seem a little flabby. The Heart Broke In has a Dickensian cast list, identifiable more by their eccentricities than plausible character traits; but in a literary culture that rewards narrow little books by sixtysomething white men about what it's like to be a sixtysomething white man, Meek's range, humour and boldness are a joy. The Heart Broke In doesn't always have the narrative grip of The People's Act of Love or the emotional power of We Are Now Beginning Our Descent, but it's a readable addition to this justifiably acclaimed writer's oeuvre.

It's hard to know exactly how to describe James Meek's addictive new novel. Philip Pullman has suggested that it might be a "moral thriller", and that seems a good place to start. The Heart Broke In is a story about families and betrayal, genetics and inheritance, sex and responsibility in the post-religious world  and also about parasites, cancer, time, birth, death and forgiveness. It starts with a powerful hook  will a married man be exposed for his affair with a 15-year old girl?  and whizzes along for most of its 550 pages, via plots and subplots encompassing blackmail, murder and sexual infidelity, leaving the reader excited and impressed and, if a little confused, then enjoyably so. With its mixture of heavy scientific detail and lurid plot twists, it vaguely resembles a mid-career Ian McEwan novel. But it's considerably odder than that.

Ritchie Shepherd, the former sex-god frontman of the rock band Lazygods, now in his paunchy and self-indulgent 40s, is running a faked-up talent show called Teen Makeover, and having sex with the underage talent. He's fine about this, even though it threatens not just to jeopardise his marriage to a former bandmate, Karin  "He'd discovered that he felt no shame about cheating on Karin until she found out"  but also to put him in prison and rob him of access to his children. His sister, Bec, a pretty, clear-eyed malaria researcher, is engaged to Val Oatman, the editor of a rightwing tabloid which inveighs against "immigrants, grasping bureaucrats, socialists, workshy spongers, amoral celebrities, trashy nouveau riche types, sexual perverts and traitors". It's a relationship that she has entered into without any clear motivation  "her behaviour outside science seemed quite random to her"  and she decides to break it off. Val is deeply displeased; and unfortunately for Ritchie he is, like the Daily Mail's redoubtable Paul Dacre, a great believer in the power of muck-racking celebrity journalism to uphold family values.

Next, Bec meets Alex Comrie, once Ritchie's drummer and now a geneticist whose groundbreaking work on cancer-fighting "expert cells" may or may not have the potential to delay or suspend human ageing. Alex, who appears to be at the milder end of the autistic spectrum, has decided that he desperately wants children: "It was one thing to talk about evolution but having children was the way to be part of it." His previous relationship has foundered with the failure of IVF. Meanwhile, Alex's uncle and colleague Harry, whose work he has continued, is dying. So his unhappy Scottish family is briefly driven together again, including Alex's downwardly mobile, sexually careless younger brother Dougie; and Harry's son Matthew, a joyless Christian who has been partially disowned by his atheist father.

In short, The Heart Broke In is an exercise in the now-popular neo-Victorian mode, or perhaps neo-19th-century mode, since like so many writers in this vein Meek looks primarily to the great Russians rather than their English equivalents. It features a large cast of characters and perspectives; it makes forays into various hot-button topics, such as the press, privacy and morality, and the whole Richard Dawkins God Delusion controversy. Like so many 19th-century novels, it centres on the ripple effect created by individual moral decisions, particularly those made by women; it builds up slowly to the grand dilemma proclaimed by the blurb: "Would you betray your lover to give them what they wanted?"

Where it is distinctive is in its semi-mystical scientific focus, and in the peculiar pitch of Meek's writing: he is a novelist of Dostoevskyan intensity and seriousness, who occasionally yields to the impulses of the airport thriller. There's a lot of scientific detail concerning reproduction and the organism's place in time (much of it, as far as I can tell, made up by Meek). Bec allows herself to become infected with a haemoproteus, a virus which offers some protection against malaria, which she names after her father and becomes surprisingly attached to. The title, incidentally, is a reference to a complicated joke concerning the role of parasites in evolution, which remained slightly opaque to me. Meanwhile, Val takes a distinct turn for the Bond villain as the story proceeds. He has a lair, an old-fashioned boardroom high up in a skyscraper, decorated with adulatory front pages about public figures. Turn these framed pages round, though, and "OLYMPIC GLORY" becomes "CHEAT" and "DRUG SHAME"; the model on the red carpet becomes the crone snorting cocaine.

Meek is a former reporter, who has written a lot of beady-eyed, elegant journalism from war zones and other disturbing places, at home and abroad. He is best known as a novelist for The People's Act of Love (2005), which featured stranded Czech soldiers, cannibalistic convicts, and a utopian community of voluntary eunuchs on the edge of Siberia just after the Russian revolution. His writing retains a certain enthusiasm for the visceral and exotic, and an impatience for the flabby compromises of modern Britain, described in his last novel, We Are Now Beginning Our Descent (2008), as "a society that could not accept it had more than it knew how to console itself with". There is a persistent, alienated sense that all is not well beneath the comfortable exteriors, which can shade into a portentous cynicism. Of Ritchie's shag-pad, we learn: "The estate agent called it a Juliet balcony. It looked like bars designed to defend the block against the mob."

The Heart Broke In is seldom less than compelling. It also has many terrific individual episodes. Meek is good on slightly messed-up family relations. He has a nice sense of the absurd: there's a very funny sequence set in Papua New Guinea, featuring a libidinous ornithologist and his garrulous partner. The main plot, however, becomes overwrought as it reaches its climax, and his prose and characters sometimes strain under the weight they are required to bear: the morally reprehensible Ritchie is something of a straw man. Overall, though, you have to admire the scope and ambition of this operatic saga  even if there are a few bum notes during the arias.

 James Meek will be appearing at the Edinburgh International Book festival on 27 August.