Lore is wonderful <3 I consider myself something of an expert. In actuality, I'm just a loner who enjoys reading uesp.net... but I prefer expert.
You should hit up http://www.imperial-library.info/ then. Contains every in-game book, and the obscure texts. Also, don't use summaries as source of information, refer to the primary source.
And the Necromancer's Moon is actually Mannimarco the god, whose only purpose is to eclipse Arkay, the lie of a previous age.
As for vampires, I'd refer to the daedric prince of nightmares as to why they cannot stand sunlight.