Nightmare Alley is a seedy journey into carny world. Here's an excerpt of a summary from Book Balloon:
At a seedy traveling carnival in Depression-era rural America, amateur magician Stan Carlisle is making a name for himself. But he’s not content fleecing the rubes for nickels and dimes. He wants more. When he gets hold of a number code he sets himself up as a mentalist; he hooks up with the carnival’s Electric Girl Molly and the two of them start working in vaudeville. But that’s still not enough for Stan and his grudge against anyone who has more respect and money than he does. He joins forces with Lilith, a coldhearted psychiatrist.
The movie of the book was made in 1947, starring Tyrone Power and Joan Blondell.