The Devil in the White City by Erik Lawson
Two stories in one book. Both take place in Chicago leading up to and during the World's Fair in 1893. And that's pretty much where the similarities end.
One story revolves around the planning, building, operating of the Fair itself. The second focuses on a handsome, charming sociopath, who charms, seduces and kills an unknown number of women (and possibly some men) not too far from the Fair. He actually takes advantage of the Fair and the numerous amount of people it brought to his door.
Some may argue that the stories are disjointed. They're certainly not related other than by time and location. But they provide relief for each other. When the Fair story starts to become stagnant, boring and too much fact and architecture details, the author switches to the murder mayhem. And vica versa for when the murder story becomes too dark and creepy.
What makes this book so great is the ability of the author to insert suspense and intrigue into the story. And I don't mean just the murder part. He creates cliff hangers and weaves suspense into the dry facts of building the Fair. There's also lots of interesting tidbits like how Shredded Wheat and Pabst Blue Ribbon, among many others, got their start at the Fair.
This book is a fantastic read. If you like dark and twisty. If you like history. This is a great book.