@Smash: Not really, you pretty much need a Magic score to really make use of most of this.
There is some information on the various Bug Spirits, Shedim and such so as a GM it can be useful as a source, but is not dead vital for a non-awakened type.
Although of course knowledge is power and knowing what the competition (be it adept or bug) can do is never a bad thing, but again depends on the player.

@Apple Ally Spirits and their creation are in there.
Possession looks interesting and am sure there will be many debates about it now.
2 main points:
a)For a spirit possessing a body to be able to increase their Physical stats, the Force of the spirit has to be higher than the stat and even then the bonus is Force/2(rounded down).
So if you have 4s in physical stats, one would need to have at least a Force 5 spirit to raise the stat and then just by 2. So no more mini boosting with low end level spirits.
If possessing another the mental stats and special abilities are that of the spirit, which means a possessed TM has no access to resonance while possessed.
If channeling through themselves, mana spells take the lower of the Mage or spirit's mental stat to resist and both take the damage.
The Force of the spirit also reduces Wound modifier by the Force of the spirit, so they can take a licking and keep on ticking (until they keel over)
b)Now a mage not of a possession tradition can learn the Channeling Metamagic to possess only himself (while still maintaining general control of body and such) rather than let the spirit materialize or manifest.
So a spirit does not need to have the possession power itself in this instance.
They have to be of a possession tradition if they want to use a spirit capable of possessing other persons or items still of course.
Think this will be really useful for the mystic adepts, but it means even a normal mage in a pinch can 'power up'.
There is more little bits to it but these two are the highlights that many will be talking about and debating concerning possession/channeling I imagine.
Before you panic about possessed mages kicking tail, Exorcism is a new metamagic and works with your Banishing skill to help bring those guys hopped up on spirits back down a notch.