It covers the nature of the life force and blood, summoning, bloody miracles, blood sorcery, the nature and types of different kinds of blood sacrifices, bloody enchantments, concert casting and Games Master rules on blood sacrifices and bloody campaigns.
What he said!
If you are interested in building necromancers, I recommend tracking down a copy of the Necromantic Arts book for MRQ II. It's not a perfect book by any means (having been hastily converted from MRQ I), but it does contain some useful goodies. Hopefully some of the better content from this book will resurface in future Legend releases.
Blood magic may still be very useful for you if your necromancer will be engaging in human sacrifice. There's also a nice section on the Summoning skill on pp.73-96 of the book that may be very useful to you.