So I'm going to a book signing...

[monster]

This is what one of my favorite authors says on her website:

Please note: books are usually available for sale at events and I will happily sign new ones. Due to encroaching painful arthritis, particularly in my right hand, I have to limit signing of old editions so please be considerate about this. It is also polite to remember that our hosts at the venue are doing this in order to sell new stock.

I like Zen's idea, but otherwise maybe justr pick your favorite of the others and explain why it's your favorite when you ask them to also sign it.

You could perhaps look on their website to find out how they feel about such requeats?