I don't often read comedy books, they tend to try too hard to be funny at every possible moment; they just don't know when to quit and give the reader a breather. Bill Fitzhugh's, Pest Control, is an exception to this, it being highly humorous, but careful not to overdo it.
Basically, the story centres around the character Bob Dillon, who dissatisfied with the use of poisons to kill bugs, such as cockroaches, etc., quits his job to go freelance and do the same job with his specially bred Assassin Bugs. He advertises his services as 'The Exterminator' and accidentally becomes of interest to those who hire hit-men, and, in turn, the real hit-men who see him as competition. A misunderstanding compounded by some coincidental killings which Bob had nothing to do with. Bob does get to try his assassin bugs out, too, but they prove to be as big, and in some cases a bigger pest, than the pests their meant to control.
This is a well written, really fun book to kill a lazy weekend with.