I have always been fascinated with much of modern American history dating from the communist witch hunts of the 50's through to Watergate and the Frost/Nixon interviews. It's this back drop that Ellroy uses as the basis of his Underworld USA trilogy (Tabloid is followed by The Cold Six Thousand and Blood's A Rover) and whilst much of what happens is based around real life moments in history such as J. Edgar Hoover's continued crack down on communism and the Bay of Pigs fiasco, the central figures are entirely fictional, as are their actions. The Kennedy's, Hoover, Jimmy Hoffa and Howard Hughes are all prominent figures in the narrative but this is Ellroy's take on America and, as such, there's a seedy underbelly that is exposed and a world where everyone, no matter how good their intentions, ends up corrupted or chewed out.
Whilst there were certain historical moments that were skimmed over (the Cuban missile crisis is only mentioned in passing), for the most part, the book is near note perfect. The initial set up of labyrinth connections and sub plots pay off in spades as the narrative is given room to breath in the middle act, all of which is neatly rounded up in the build to the assassination of JFK. There are crosses, double crosses, double and triple agents whose loyalties are tested when all sides they're infiltrating end up at odds with each other. There are no heroes here, only varying degrees of filth and even the historical figures, most noticeably Jack and Bobby Kennedy and J. Edgar Hoover, are portrayed in a scathing light.
As a complex tale of greed, corruption and political espionage it's a winner. As a character study of those involved in politically motivated organised crime you end up hating everyone. And the main crux here is involvement. From the blistering set up, Ellroy's prose and staccato, urban language put you in the time frame where violence is a necessary evil and casual racism is a way of life (one character is a die hard member of the Klu Klux Klan).
If you haven't read any Ellroy I recommend you start here. Hand's down one of the finest novels ever written. It makes you feel somewhat dirty afterwards but it's seriously compelling and gripping stuff.
It was Time magazine's novel of the year (1995) for a reason.