If you asked me who was the major medieval figure I know the least about, the answer is pretty easy: Charlemagne. I haven't intentionally neglected him, it's just that life is short and learning long.
Wordhoarder Jeff Sypeck seeks to change that with his new book Becoming Charlemagne, which is aimed at popular audiences rather than scholarly audiences (translation: promises not to be boring). I haven't read it yet, but you can find a review of it here.
By the way, the reason I haven't read it yet is that I don't have a copy. In a totally, completely unrelated aside, there are now only 21 shopping days until Christmas. *wink*wink*nudge*nudge*