Hitchhiker's, volume 3.
Mostly about Krikkit - and the Bistromathic Drive, which is better than mere Infinite Improbability.
The immortal Wowbanger the Infinitely Prolonged gave himself the task of insulting everyone in the universe - individually (but nearly did Arthur twice).
It has the usual wonderful Adamsness:
The "knack" of learning to fly is to "throw yourself at the ground and miss".
"One thing has suddenly ceased to lead to another".
Slartibartfast, who has one of the best names in literature, "wrote a monograph to set the record wrong about one or two matters he saw as important".
"Time travel is a menace. History is being polluted. The past is now truly like a foreign country. They do things exactly the same there".
"They obstinately persisted in their absence".
To attack a transdimensional planet you need to work out how to "fire missiles at 90 degrees to reality".
"sat in darkened rooms in illegal states of mind".
"One of the least benightedly unintelligent organic lifeforms it has been my profound lack of pleasure not be able to avoid meeting" (Boris took that idea with "I couldn't possibly fail to disagree with you less").
Brief summary and favourite quotes from the other four of the five books, as follows:
Hitchhiker's Guide (vol 1): http://www.goodreads.com/review/show/107767859
Restaurant at the End of Universe (vol 2): http://www.goodreads.com/review/show/107768059
So Long, and Thanks for all the Fish (vol 4): http://www.goodreads.com/review/show/107768203
Mostly Harmless (vol 5): http://www.goodreads.com/review/show/107768298