The Restaurant at the End of the Universe: The Hitchhiker's Guide to the Galaxy, Book 2

The Restaurant at the End of the Universe: The Hitchhiker's Guide to the Galaxy, Book 2 by Douglas Adams

The second Hitchhiker's Guide book is comedy couched in nihilist philosophy. The earth has been destroyed just before it produced the question for life the universe and everything. (The answer was 42.) The gang are traveling around with some bizarre gadgets (including glasses that make things go black to help avoid bad things). The paranoid android continues to be negative, but can help them get places. They are hungry and end up at the Restaurant at the End of the Universe. There is some time travel involved, so people can go, watch the end of the universe and then return back home. The restaurant includes animals that are bred to be eaten. The cow comes out and asks people what part of them they would like to eat. 

The gang ends up stealing a totally black ship and eventually end up on early earth. They run into primitive cultures, as well as a culture that has formed bureaucracy before innovation. (They need market research before producing the wheel.) There is also a group of "unneeded" people that were sent away from their planet under the guise of being the first to inhabit a new world before their planet is destroyed. The book includes some humorous explanations for hard to grasp processes (like the beginning and end of the universe.) There are plenty of funny moments as well as parts of interesting observations of the silliness of people, especially in the context of a vast world.