James Ellroy: "I sit for a lot of time in the dark thinking big deep dark thoughts."

James Ellroy: "I sit for a lot of time in the dark thinking big deep dark thoughts."

Be gentle with James Ellroy, the hard-boiled, self-styled "Demon Dog" of American crime fiction, for he is nursing a broken heart.

At first read, Blood's a Rover (Century, November) is a sprawling and enthralling conclusion to Ellroy's Underworld trilogy, which examined the underbelly of America in the 1960s and '70s. Over the course of more than 600 pages and set between 1968 and 1972, it spans the establishment's attempts to undermine the black civil rights movement, voodoo in Haiti, the election of Richard Nixon and the mental decline of Howard Hughes and J Edgar Hoover.

Ellroy talks in the same clipped sentences of his novels and initially describes the novel thus. "The holy conjunction of man and woman. The war of ideals. The extremity of love. The necessity of belief. The conviction that God exists. The human being's inherent spiritual need to change. The corruption of power. Lonely hearted men in love with the swingingest, grooviest lonely hearted women in history. These are the major themes of my novel."

His deadpan manner and rather stylised public persona leave you never entirely sure whether he is joking or not. But the first read doesn't give you the full picture. Ellroy says the book's origins lay in a "meltdown" he had during a book tour in 2001.

This led to the break-up of his marriage to the writer Helen Knode. "It's corny but it melted the core inside of me. And then who walks in? JOAN." He says "Joan" like an atonal buzzer. "Joan kicked the shit out of me and I thought: 'Holy shit, I have to write a book.'" His relationship with Joan ended messily three years ago and the book is dedicated 'To J M Comrade: For Everything You Gave Me.' "I wrote this book in heartache and blood because I loved that woman very much and it didn't work out. A couple of days ago I got the publisher to Fed-Ex the book to her and I haven't stopped boo-hoo-ing since."

Last man standing

The real-life Joan inspired the character of Blood's a Rover's Joan Klein, a left-wing subversive at the centre of the book. Klein is the great love of the three characters that drive the narrative— Dwight Holly, J Edgar Hoover's pet thug, Wayne Tedrow Jr, heroin runner to Howard Hughes (among others) and Donald Crutchfield, a wannabe private eye with a penchant for being a Peeping Tom.

It is the immature Crutchfield, constantly underestimated by his peers, who emerges as one of the most fascinating characters of the novel. During the book, he becomes obsessed with the murder of a tattooed woman (which eventually leads him to Joan), gets involved in the campaign to undermine the Democratic presidential campaign and get Richard Nixon elected and carries out anti-Castro raids in Cuba. "He's the dipshit American kid as a genius," Ellroy says.

"Everybody underestimates him. When I created him, even though this other man was on a big stage, I thought he was like [Ronald] Reagan. Everyone underestimated him. And he took everyone down. Gorbachev, Carter, everyone. Crutchfield is the last man standing at the end of the novel."

Off the grid

Despite the novel's themes of men trying to deal with nefarious political subversion, race and political intrigue, Ellroy is adamant that he did not use the novel to examine contemporary America. "I live in a media-free zone," he says. "I don't have a cell phone. I don't have a computer or television set. I have an assistant with email who takes care of shit for me. I catch very, very little of the world. I observe and can read people very well. But I haven't followed politics assiduously in years.

"When I conceived this novel of political intrigue nothing from the current world was popping into my head. When I conceived the novel, Obama had not been elected to the Senate and I didn't even know his name. It is a book about race and politics and if I can cash into that then great. But it did not have a direct effect [on the book]."

While his recent novels have moved from the 1950s to 1970s, Ellroy says it's unlikely that he will examine America in the 1980s or 1990s in future writing. "Too many people are still alive," he says. "I got to go back. I get to have distance between me and the setting. You can look at any particular administration in American history and find abuses of power, personal and political corruption and military intervention. You can find it at any time but the newer shit I'm not conversant with. I don't live there. I want to live in the America before my birth and during my early cognisance."

Despite Blood's a Rover's tales of right-wing men and the horrible things they get up to, the actual politics of the book are not entirely clear cut. None of the men emerge unscathed from their actions. "My books are often misinterpreted," Ellroy says. "The Christian morality of them is often misunderstood.

"All kinds of political views are attached to me. I like talking about it with readers, I sit for a lot of time in the dark thinking big deep dark thoughts."

Ellroy will get a chance to meet his readers when he visits the UK later this year. "I love that shit," he says. "But I can see it now. I'm doing an event in San Francisco. Who walks in? Joan. Oh, it's a life sentence..."