Every so often a book comes along that is so puzzling, so brutal and so honest that you almost want to keep it a secret. But this kind of book is also too good to keep to yourself — you want to allude to it and pepper it into conversation in the hope that one day, just maybe, someone will recognize the title. And it will feel like the two of you are in a secret club, sharing this secret story and its secret world of violence and triumph and destitution.

You’ll be glad to know that one of those books has come along in the Booker Prize longlist, in the form of Gabriel Krauze’s “Who They Was.” The novel is a brilliant outlaw story set in the violent streets of South Killburn, one of London’s outlying neighborhoods. It is raw, baroque in its expletives and poignant in its exploration of a young man’s descent into the madness of London’s criminal underworld.

“Who They Was” is Gabriel Krauze’s debut novel, an auto-fictitious account inspired by his early life. He narrates in the first person, as Gabriel Krauze — a.k.a. Snoopz — meanders through downcast streets, slinking through apartments and blocks where “rectangles of yellow float in unshakeable loneliness: windows in the concrete towers of South Kilburn.” But in between robberies and prison-stints, Snoopz is pursuing an English degree at Queen Mary’s University in London.

Woven into the story are two different lives vested in one person — a criminal and a student — each pulling Snoopz a different way, down paths that diverge more and more as the story progresses. The prose embodies that same conflict, alternating between slang-filled, chaotic stream of consciousness and clean, cutting soliloquy.

The currency of life is different in South Kilburn. Wealth is just as often measured in “boxes of work (heroin)” as it is in dollars. Snoopz’ friends don’t have jobs, they “make moves” selling drugs, robbing outsiders and sometimes their own “bredrin.” People are shot in broad daylight and their killers are never caught. Snoopz knows that these violent delights are almost unheard of in London proper, but to the people of South Killburn, “these incidents are just the punctuation of their reality.”

The reader may then expect a different atmosphere when the story diverges into the classroom, for Snoopz to affect a neater attitude to reflect this new setting, but this is not the case. Professors address the narrator as “Gabriel,” but he answers their questions as Snoopz, informal and often irreverent. He is determined to graduate, but feels that his true self belongs to that other world, belongs to the pursuit of twisted honor in theft and violence. Despite his love for literature, he refuses to follow the straight-and-narrow and become a professional drone.

The reader is never allowed to forget that this is a skillful novel, that the narrator is as much a poet as he is a bandit. Grungy sentences like “I’ve got the p’s and Not Nice has the connec for big bits of food (drugs) and he knows everyone round the end who’s shotting punk” are followed by sublime asides: “When I go (to prison) I’m gonna have to fold up all these other parts of myself and stash them away in the caves of my being.”

But these modes aren’t just relegated to their respective settings. The narration isn’t just clean and proper when Snoopz is at college, debating Nietzche. And it isn’t just loose and raunchy when he is around his South Killburn friends. Where Krauze strikes gold is not in placing these two voices at odds to highlight Snoopz’s split identity or characterize the setting, but in employing them to greater effect as reliable emotional indicators.

It’s like that old rule of musicals: When the emotion becomes too intense for talking, sing, and when it becomes too intense for singing, dance. Krauze performs the same progression in the novel, switching to tight, spare prose when the emotion of the story is too great for plain speech, slang and run-on sentences to capture the extremes. Just as in a well-performed musical, the transition is effortless and lends many moments an unexpected impact, leaving the reader to wonder: How the hell did he do that?

Krauze has written a sobering treatise on a way of life that is easy to ignore, but he has also shown the beauty in it. The cold life, the life where stabbings and shootings are commonplace and violence hangs in the air, is not so cold after all. There is emotion everywhere — triumph and failure, growth and death, brothers sent to prison and mothers left at home to weep for their sons. Snoopz’s indifference to it all is a charade perpetuated not by a desire to be cold and diffuse in the face of danger, but by a need to be.

Daily Arts Contributor Julian Wray can be reached at jwray@umich.edu.