"The Cold Six Thousand" is a novel by James Ellroy, published in 2001. It is the second book in the Underworld USA trilogy, exploring the dark underbelly of American society in the 1960s. The story follows multiple characters, including Los Angeles police officers and FBI agents, as they navigate crime, corruption, and political intrigue. The narrative is known for its fragmented style and complex structure, reflecting the chaotic nature of the era. Themes of violence, conspiracy, and moral ambiguity are prevalent, as the characters grapple with their roles in a society marked by paranoia and betrayal.