Can I put a Keynote presentation in a Keynote presentation? I have a bunch of related topics I teach.  Each topic has its own Keynote presentation.

I am making a new class which teaches all the topics together.  I would like to make a Keynote presentation for this class using the existing presentations.  I don't want to copy the slides, that will be a maintenance hassle to change both copies.

Can I embed a Keynote presentation in a Keynote presentation?
You can create an iBooks presentation which allows you to do this. Whenever I have multiple presentations in one topic, I combine them into an ibooks, which allows you to embed several keynote presentations onto one "slide" or "page". Plus it looks really good -- you just click (or tap in iPad) and the embeded keynote will display. Hope this helps.