So I'm going to a book signing...
 

and I've never been to one before.

This author has written 16 books, and when I buy the one at the signing, I will have 15.

Is it ok to take all my books by this author to have him sign them or just stick with the one I bought? Somewhere in between?

What's the etiquette here?

I've never been to one, but friends who have indicated there was a loudly-announced limit to the number of items you can have signed. Usually, it is just the one book you are buying at the signing, and maybe one additional, if the author doesn't mind. If it's a very small, local author, they may be thrilled to have such a dedicated fan. But if he has published 16 books, chances are good there will be a line of other people who won't appreciate you carrying a stack of 15 books.

Now that I think about it, I did go to one "famous person meet & greet" that included the ability to have something signed, though they were not authors--and the emailed information about the event beforehand specifically said you get one photo and one signed item, no more.

I've been to several, and usually it's just the book that is being promoted.

Sometimes you can get one other item signed, but that's rare, if it's a big name.

Just to say - thanks for the question!
I'm going to go to my first one in September, and I was mulling over the same thing.

In this case, he only has two books out (the one he's launching and one previous) so it's not as big a deal. But I was wondering if I could take something else to be signed. Like my theatre programme. I don't mind really. I've never had a big thing about a scribble on a piece of paper - it's the face-to-face I'm excited about. I've been able to go up and speak to two of my heroes, and it meant the world to me :)

I would definately take the programme along to be signed Sundae.

I only have one signed copy of anything: an autographed copy of The Crucible by Arthur Miller :)

How about you clamp all fifteen books together, hand the chap a sharpie, and ask for a big signature that spreads over the spines of all of the books at once? It'd be better if you had the 16th book though.

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

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?