Colm Toibin cites early last century as the only period in which Henry James might have accepted his homosexuality. Toibin's novel follows the writer in the years immediately before that period, when his work waned before his last spurt of genius. He depicts a sexually tense friendship between James and Hendrik Andersen, a young Norwegian sculptor. When Anderson enters James' study to find a library of books by the middle-aged author, he asks whether James had always known he would write: ''Did you not once plan it all? Did you not say this is what I will do with my life?''

'By the time he asked the second question, Henry had turned away from him and was facing towards the window with no idea why his eyes had filled with tears.'

No further explanation for the tears is offered. Toibin skips to later that night. James is in bed, pensively imagining Anderson's body. Toibin crisply describes the floorboards creaking while the younger man undresses in the next bedroom. But he avoids spelling out deeper sentiments, leaving us to assume that the sudden emotion in the library was a bolt of the solitude, failure and untapped desire James endured for his work. Toibin is always careful to let the reader imagine the mind of James.

Interviews with Toibin have been sprinkled with references to James and Ernest Hemingway for more than a decade. The Master offers even more allusions to two writers whose distinctive style makes them easy to parody. We all make fun of Hemingway's terse, tough pose. But as Tobias Wolff argues in his recently released novel, Old School, most miss the way Hemingway shares his unmanly weaknesses. Hemingway, says Wolf, deliberately invests enough autobiography in his characters to make them more believable. We also laugh at the mannered aloofness of James, disregarding that this distance allows readers to get closer to characters or invest more in the mystery of The Turn of the Screw.

Toibin recreates James with thorough research, building fiction that sticks to facts. He leaves uncertainties to Jamesian distance or, by borrowing from Hemingway, offers insights into life as a gay, middle-aged writer who craves solitude yet feels lonely. The conventional image of James suggests he astutely toyed with privileged society. Toibin's James, though, uses wit and tact to hide from intimacy. When the writer Constance Fenimore Woolson hints that she is looking for more than friendship from James, he uses cruelty to distance himself from her. She commits suicide.

'When everyone else had fire in their blood, he was calm,' Toibin writes. 'So calm that he could neither read nor think, merely bask in the freedom that the afternoon offered, savour, as deeply as he could, this quiet and strange treachery, his own surreptitious withdrawal from the world.'

The withdrawal can be funny when not pitiful. Toibin has James too self-conscious to sack his alcoholic servants. His social guile hides their incompetence from visitors. Easily spilled soups and gravies are removed from the menu at Lamb House, the newly acquired 'necessary shell'.

As well as literature and sexuality, Toibin and James share Ireland. Toibin jokes in interviews that James is the great Irish writer of last century, a swipe at his country's neglect of Presbyterians who prospered in America after being forced to leave Ireland. James is depicted as indifferent to his Irish heritage. When visiting Dublin to escape the failure of his play in London, 'the sullenness of the Irish' makes James snobbishly uncomfortable.

The Master matches any biography of James for accuracy, and any James novel for readability - at least for those who tire of long James sentences. Toibin, to borrow one of his descriptions of James, beautifully 'works his imagination' on the mysteries of his character's psyche.