They Shoot Horses Don't They? by Horace McCoy

The Great Depression led people to take desperate measures to survive. The marathon dance craze, which flourished at that time, seemed a simple way for people to earn extra money, dancing the hours away for cash, for weeks at a time. But the underside of that craze was a competition and violence unknown to most ballrooms. A lurid tale of dancing and desperation, Horace McCoy's classic American novel captures the dark side of the 1930s.

(Serpent's Tail)