We were in Borders Bookstore, and I heard a lady asking a clerk about "that woman author who writes mysteries that all start with a letter." She wanted to get some books from that series for somebody she knew.

Well, I'm an authority on all things related to detective novels, and here was a chance to flaunt my knowledge.

I walked over and casually said, "The author is Sara Paretsky." I then spelled out "Paretsky." She thanked me, and I walked away, a good deed done. The customer and the clerk were now on the right path.

About ten minutes later, it hit me: it's Sue Grafton. Sara Paretsky writes the V. I. Warshawski novels. Sue Grafton does the "alphabet" books starring the intrepid Kinsey Millhone.

I wanted to slink away in humiliation. The clerk had probably found the right author and told the customer, "That guy doesn't know what he's talking about."

I am not, after all, infallible.