I first encountered John Kendrick Bangs when I worked in my father's book store. One of the rare books that he had was a copy of A House-Boat on the Styx. I enjoyed it immensely, though I certainly didn't understand all of it.
The Associated Shades is a Gentleman's Society of the shades of famous historical (and occasionally fictional) people. They while away their days in their clubhouse, a houseboat on the river Styx.
The point of the book is the banter between the various characters. Each chapter delves into a different subject. It's a delightful read, equally suitable for reading bits casually while waiting for a bus, or for sitting down and reading through the entire thing in an evening.
There are also three sequels available, Pursuit of the House-Boat, The Enchanted Type-Writer, and Mr. Munchausen: Being a True Account of Some of the Recent Adventures Beyond the Styx of the Late Hieronymus Carl Friedrich, Sometime Baron Munchausen of Bodenwerder.
This series coined the term Bangsian Fantasy, a fantasy genre where historical and sometimes fictional characters meet in the afterlife to have adventures or a chat.