Just finished Underworld by Don DeLillo. An absolute monster of a book. I started at Christmas but not being going hammer and tongs at it. Bloody hell, it takes you all over the place. From Cold War America in the 50s through to the late 90s when it was written with a huge cast of characters including J Edgar Hoover, Sinatra, Lenny Bruce etc. The thin thread is following the baseball of 'The Shot Heard Around The World' from the famous match in 1951 when the Giants beat the Dodgers against the odds - and where the baseball itself ends up. But there's loads of other sub stories intertwining and snaking through it. There'd be a character on page 150 that doesn't appear again until page 725 and I'm thinking, 'hold on, who's this then?' I found a website with a list of characters that I occasionally had to refer to.
It's not a book that you can say it's about such and such but to me it seems like it's a snapshot of America at a certain time, nuclear power, waste management, Soviet weapons, the Cuban missile crisis, New York's slums, AIDS, baseball, the age of the internet, the Catholic church - and more. It's just hard to describe and so looong.