Fred Shapiro, the editor of The Yale Book of Quotations we interview in this week's "Behind the Dictionary" feature, recommends these books on the history and importance of quotations:
The Quote Sleuth by Anthony W. Shipps
Nice Guys Finish Seventh: False Phrases, Spurious Sayings, and Familiar Misquotations by Ralph Keyes
They Never Said It: A Book of Fake Quotes, Misquotes, and Misleading Attributions by Paul F. Boller
The World in a Phrase: A History of Aphorisms by James Geary