It can read PDF, RTF and TXT files, so you can easily convert a kindle or other epub into those formats and do it that way, but yes, you can put a full book into it.
Thanks for the early preview. How are they going to profit from this? Right now they bill for everything on their site, cant imagine they will step on their own toes
The feature is actually basically available on their site now under "projects" and it's only available for those paying at the creator level or higher. As far as I can tell, it uses up your tokens/words at the same rate as their normal text-to-speech, which makes it very costly to do long form projects. But I'm assuming once the app is out of beta that it will be tied to that.
