Well, there's no setting because the DB view gives you a tab for that. So you can view them sorted by downloads, recent, favourite, title, author. And you can even sort them backwards and forwards.
But since actually finding a book in that mode is so cumbersome (do you want to go through 30 pages of books in the author tab?) I never use it. There's also a search book by title feature, but for navigating, you just can't beat the folder view.
If they'd just added another tab for the folder view or a hotkey that switches between the modes you could have best of both worlds but ... meh.