I feel I'm missing something really obvious, but I hit BLM 50, and I still haven't spotted the quest for Manawall, let alone the spells later, and AF...

I've scanned the usual suspects, the THM guild, the BLM guy in Sacrarium - and in and around town, though - nothing shows up.

What am I missing here? I tried searching around, but I can't find any reference to it either... Thanks in advance!