If not only a remarkable noir (and it is) "The Gilt Kid" is an important document of a certain type of crime underground life in London 1930's. London is almost a character in itself in this novel, along with our anti-hero The Gilt Kid, called that because he's blonde.
A habit criminal who specializes in breaking into London flats and offices to steal, is sort of on an existential course between desire and living day-by-day. He's lonely but can't articulate his world via language, but by action he sees each day as an adventure of sorts - but alas, a very limited adventure. He basically can't see his future more than a few days at a time.
There is a Marxist bent in the story, because The Gilt Kid struggles with reading "Capital" but with little understanding, but he sort of gets the drift of it. The classic aspect of the book is the focus on the side characters that he meets up on the streets of Soho. Hardcore slang, lots of smoking and drinking milkey tea - along with the occasional brandy and various beers. Its a dead-end street, but a road that is still colorful and kind of beautiful in a depressing way