Scholar Fred R. Shapiro is an authority on quotations and the editor of the seminal Yale Book of Quotations, a compendium of over 12,000 bits of wisdom by notable people through history. A Mount Everest of quotes! Which got us wondering: Why the fascination with quotes? And how do we know that Mark Twain quote was actually quipped by Mr. Clemens? We called up Fred to find out:

VT: Why are people fascinated with quotations?

Fred: I think there are lots of motivations. In the business world people seem to like slogans and phrases that inspire them to have better team work or be more creative. I think people value quotations from literature as a way of encapsulating the larger work or reminding them of something they enjoyed reading. Something like a proverb is very meaningful to many people who guide their lives based on them, or on other sayings that they find comforting.

VT: Has the interest in quotations been a long-standing one?

Fred: There were quotation dictionaries as far back as the 1700s. The idea then was to capture the highlights of literature and Bible verses. Today, many people include quotes in their email signatures, and greeting cards often have quotations, so I think now there's actually more interest in quotations then there's ever been.

VT: The Yale Book of Quotations contains over 12,000 entries. How did you decide which quotes to include?

Fred: My main criterion was famousness. I used state of the art research techniques to be much more comprehensive than other quotation dictionaries, including employing certain types of online searches to scientifically look for famous quotations. I also consulted prior quotation dictionaries just to make sure I didn't miss anything.

VT: What about falsely attributed quotations? There must be lots out there.

Fred: That's something that really surprised me when I was editing my book. I knew that there was a lot of folklore about famous quotations but I was astonished to find that even the most respected quotation dictionaries such as Bartlett's Quotations are really full of errors, and that little research was done. When I started my book I thought, well, maybe I'll find better information than what's in other books for a few dozen famous quotations. In fact, I was able to do that for thousands of famous quotations -- and was really surprised by how improvable the information contained in other books was.

VT: Can you give us an example?

Fred: A good example is "Go west, young man," which all the quotation dictionaries and even the Oxford English Dictionary say originated with an editor in Indiana named John Soule. In fact, I found in my research that everything that Bartlett's and the Oxford Dictionary of Quotations, as well as the Oxford English Dictionary, say about this quote is wrong.

My research assistant at the Library of Congress read through the entire Terre Haute (Indiana) Express in 1851, which was supposedly the year when this editor published the quote. But he couldn't find it. I ended up coming up with evidence that this quote was, in fact, originally made by Horace Greeley.

Another example is "there's no such thing as a free lunch," which Bartlett's attributes to economist Milton Friedman, who wrote a book in 1975 called There's No Such Thing as a Free Lunch. But I found through my research that it was used as far back as far as 1938 as the punch line of an economist's joke.

I found these kinds of things by doing very powerful searches in databases of electronic texts, which is where a lot of my research came from. I was lucky that at the time I did my book there was an explosion of electronic texts you could search online. So I was able to trace these sayings much further back than anyone had ever been able to do before.

VT: Do these misattributions happen even with very famous people like Winston Churchill or Mark Twain?

Fred: Some famous historical figures become "quote magnets." For instance, anything that sounds folksy and humorous invariably gets attributed to Mark Twain. I researched his more popular quotes and tracked down whether Mark Twain really said them, or if not, where they came from. For the quote, "Golf is a good walk spoiled," which is attributed to Twain, I could find no evidence that he actually said it. But I was able to trace it in newspaper databases, and the earliest citation I could find there was later than Mark Twain's time.

VT: What else surprised you when you were editing this book?

Fred: I was surprised that some of the most famous and popular quotations in history were left out of Bartlett's. I also emphasized modern culture more than the other books, especially American quotations, which I found to be neglected in other books. In addition to quotes from literature and history, I included notable sayings from popular culture, sports and children's literature.

VT: How long did it take to put your book together?

Fred: Six years.

VT: Wow. Did you have a team of researchers working with you?

Fred: I was lucky I to have some very good helpers. I had research assistants, and I also connected to Internet discussion groups. An Internet group that was extremely helpful is called Stumpers, which is a network of about 1,000 reference librarians and researchers.

I would post questions on this group and often someone would go and do very good research and give me a very good answer. Some of these people were reference librarians but I also got help from a metal craftsman in Berkeley, California and tax lawyer in Washington, D.C. Some of these people got so into the project that I ended up making them official "research editors" and worked with them quite a bit.