Safire's Political Dictionary is a lexicon of political terms and their origins. Many terms used in non-political contexts today have a surprising political etymology, as documented in this book. It is a fascinating read, and an effective reference manual.
This book is weak on social terms, however, while laden with terms of bureaucracy and those used by political officials. Terms like the "cufflinks gang" (early supporters of FDR) are featured in the book but not commonly used today. Terms that are frequently used today like "RINO" and "vaccine police" are missing from this book. Political terminology does change quickly, through no fault of this book's gifted author William Safire.
This book was improved through five editions, its latest in 2008.