Does anyone know a theory website that will cover everything? Literally, everything? I've seen musictheory.net, but that stops at neopolitan chords - I wanna go further =D

If anyone could recommend me something I shall be very grateful. Also, If anyone could recommend a great book for music theory then I shall also be very grateful.

Many Thanks

i dont have any reccomendations, but if you want a book on music theory, stop by your local music store and ask them what they reccomend.
I don't know personally but the "for Dummies" book on Music Theory has been recommended a lot. I don't know if it stops short for you though...