Need help creating custom taxonomy

I’ve been working with creating Custom Post Types, and things are going great, but now I want to take things a step further and I’m not quite sure where to turn.

I think what I need to do is make a custom taxonomy field, but I’m not even positive if that’s the best approach or not.

Basically, my problem is this –
I have created a Custom Post Types page for “Authors”, where I can add new authors – basically enter the authors’ name and information about them. That part is good.

So now I want to create another Custom Post Type, this one for “Books”. When I go to “add a new book”, in addition to entering the title and information about it, I would like a drop down box to appear that has all of the Authors from my other custom post page.

Is this possible?
If so, can anybody help point me in the right direction?

Thanks so much!!