The Ancient Necromancy Incantation is not easy but can be soloed.
This quest is for a book and the 12 Incantations that Necromancers should find very helpful (similar to the Cleric spells).
The entire quest takes place on the Ilshenar facet so it helps being familiar with that area. The quest must be completed within three hours from start to finish and some segments must be done within one hour.
Start by talking to Morghadam the architect who can be found on the second level down in the Sorcerers Dungeon. Morghadam will send you to Acererak the Demilich who will give you one of twelve tasks.
If you succeed Acererak can give you the Ancient Incantation Book and all the spells. He 'may' also give you one of eighteen special items (armor, clothing and weapons).
There is a four hour cool down period before it can be repeated.