I like the new grid feature that was implemented for navigating between books.  There is something about it that annoys me, namely, that if, for example, I click the wrong book or chapter, there is no way to back up to that screen without having to first load where I don't want to be, or just canceling the whole process to start over.  Some sort of "back" button would be most beneficial.

Yes, that's been suggested, and I agree, it's annoying.  I'll see what we can do.  If it's not in 4.0, it'll be in the release just after that.