PUNishment: The Art of Punning by Harvey C. Gordon 1977
PUNishment: The Art of Punning or How to Lose Friends and Agonize People, Harvey C. Gordon, Punster's Press, 1977.
The author is a practicing attorney. This book presents puns by categories ("Animals", "Food", "Law", "Love", etc.), and then concludes with an essay on the "art", and an Epilogue consisting entirely of this: "When things get rough and you cannot seem to gain any ground, drop back and PUN." Also discusses techniques for punsters.
Second Edition. 91 pages.