SUPPOSE you've read the prison books and seen the prison movies, read Belly of the Beast, Birdman of Alcatraz, The Executioner's Song, seen Brubaker, Escape from Alcatraz, The Last Yard. Then you probably figure there isn't another tragic story from the big house, another wacko anecdote about a colourful con or a sadistic guard, another boring statistic about the failure of the penitentiary system, that you really want to hear again.

Wrong, as it happens.

Line Screw - the title, which is jargon for prison guard, is actually the only uninspired thing in the book tells the story of a man who worked for 10 years as a prison guard in British Columbia, and it's done with such wit and style and insight that it makes the subject seem almost fresh. Note the part about almost fresh. In fact, the tales that J. Michael Yates tells and the characters he draws aren't all that different from the stuff that appears in Belly of the Beast or Brubaker. But Yates has such an original, slightly skewed, but sympathetic fix on prison life that he makes the existing literature seem more than a trifle stale.

As you might guess, Yates didn't follow the usual route - whatever that is - into the prison-guard profession. He got there through an episode that would be hilarious if it weren't also so painful. Yates had a senior job at the CBC, head of public relations for all of B.C. Then he was in a car accident, a simple rearender, that brought on migraines, intermittent blindness, and memory loss. In rehabilitation, after leaving the CBC, where intermittent blindness and memory toss weren't on the job description, he turned to writing. After fully recovering, he looked for a position that would leave him time to write, and fluked into a regular shift at Oakalla Prison.

Yates seems to have the precise balance of common sense and toughness that makes a good prison guard, simpatico but nobody's fool. Nobody's pushover, either. And he seems to have got a kick out of his work, out of riding herd on the genuine villains, protecting the poor souls, schmoozing with the more savvy cons. All of which, combined with Yates's nicely rhythmic writing and sharp eye for detail, make him the ideal reporter from inside the prison walls.

Here, to give you a sense of the book's flavour, of the way in which Yates puts the reader in the grip of penitentiary life, are two of his stories:

A young and not particularly religious Muslim got drunk and stole an expensive car. He received a short sentence, his first, which he appeared to be serving with good grace. Except that one night, he inadvertently offended an old con. The old con and his friends, with nothing better to do, taunted the kid, making LIP Plots Of nasty things they planned to inflict on the kid in the morning. No one took the taunts seriously. No one, apart from the Muslim kid. He spent the night tearing his sheets into strips, braiding the strips. In the morning he was found hanging in his cell.

A veteran guard received the news from his doctor that he had incurable cancer. Probably six months to live. At work that night in Oakalla, the guard, acting covertly, swiped a prison pistol, loaded it and stood alone in the prison's segregation wing pointing the pistol at the sleeping body of the only prisoner in the wing. The guard felt absolutely calm. He had nothing to lose, he was dying anyway. Why not squeeze the trigger? Why not take out this particular prisoner? "Fuck it," the guard said, and walked away. Clifford Olson slept on.