Interesting. The blurb mentions me as an author, but I certainly don't remember writing that book. 
You'll notice my name is not on the cover.
edit: D'oh! David already said that earlier in this thread.
You've been sleepwriting again? 
Salvete Sodales!
Finally, the 5th ed. version of the 4th ed. 'Natural Magician' I suppose. After A&A I had started to fear that the production of theriacs would be all left of them.
And now I start to hope and fear. What have you done to them. Sure, the 4th ed. version needed some balancing (even though the lack of generals Magical Resistance will do very much to this end), but all those Mystic Companions in the previous sourcebooks seemed so weak compared to a hermetic magus. Well, a month or two and I will know. Arrgh, I hate waiting!
Vale,
Alexios ex Miscellanea
I was kind of happy about the A&A theriacs filling in the slot for "Natural Magician". The simplicity of the "it's natural ergo it isn't magic" take really appealed to me and the tricks that they can pull without any supernatural assistance seems spot on to me.
I've always sort of seen the order as natural knowlege + supernatural backing. Now with the importance of Artes Liberales and Philosophae in casting they fit this role even better.
I'll hold my judgement on the scholarly magician hedge tradition until I read it, but from the outside looking in I see a strong possibility of a tradition that doesn't fit my conception of what should exisit in the setting.
woOT!
Hmm.. what is a Gruagachan again? 
Eirik
Gruagachan, written up for ArM3 in Lion of the North, and adapted to ArM4 in Land of Fire and Ice (as the Icelandic "Troll sons") were/are Scottish hedge wizards. In many ways, they represent the archetype of the non-hermetic magus as they are now understood in 5th edition: their Gift enables them to learn a wide variety of supernatural abilities -- in previous editions, that made them pretty unique.
These abilities invariably include shape-shifting (a more powerful version than ArM5 Shapechanger), and traditionally extend to the laying of curses or geases, bestowing of gifts, transforming others but in ArM3, they could potentially learn every Exceptional Talent without the self-limiting factor present in ArM5.
The big downside of Gruagachan magic is that botches progressively make them monstrous (think about the worst of ArM5 twilight scars).
A few also knew the secret of (permanently) placing their soul in an object, which made them practically immortal (fatal wounds instead making them yet more inhuman), but would kill them if the object was damaged in any way.
In previous editions, you really, really didn't want to piss a Gruagach off. They are nasty.
Damhan-allaidh, against whom war was waged by Pralix and her Ordo Ex Miscellanea, was a Gruagach.
In other words: Gruagachan are the coolest concept besides the magic system ever introduced into Ars Magica.
Damhan Allaidh is a gruagach, but with several "improvements" related to blood magic. If this is because he is infernal or not is not clearly cut (well it was in the Iceland supplement, but I always disliked the fgact that every baddie seems to have to be infernal: you can be an ass*ole without being infernal, after all. If I were a demon I would watch from the sidelines comfortably eating popcorn (or souls) while they trashed each other breaking the thou shall not kill commandment and playing with sinful stuff like pride and wrath. They are damning themselves anyway, so just enjoy the show.
I am ranting now. As you can suppose I look forward to this supplement eagerly. 
The only problem with gruagachan is that they and flambeau do not mix very well due to some past missunderstandings.
Xavi
Yeah, but between twilight, immortality, and death-bed repentance, Hell probably doesn't see a lot of Gifted souls no matter how mired in sin most of them are.
On the other hand, watching a magus who has achieved immortality, confident that he's escaped his just desserts, screaming in pain and horror as he slips into infernally-tainted final twilight is pretty funny too! even if it doesn't pay the heating bill.
makes pop-corn
Anyway, does anyone know anything about the folk-witches? I don't remember them from previous editions. (Never could find a copy of Hedgies though...)
There's always opportunity for a break with the past. Appoint yourself ambassador to the Flambeau and open a new chapter in Hermetic history. 
Clan MacGruagach is cool, as they are ex-misc hedgies. But the non-Hermetic Gruagachan, well, they have hgas centuries to choose "Join or Die", so I have no sympathy for their screams.
That is plain old imperialist gibberish for you, fellow readers. Infernally tainted (thou shall kill) one, to boot. Did I hear you say something about your Jaferyia pals, Mark? Having to abandon a tradition that was old when Rome was a hamlet just because a bunch of upstarts with big guns think their newish law system is better than the highland proven traditions? No thanks.
Xavi
Just saying man, that's all. I like the Hermetic Gragachan just fine 
(at a meeting of the Cabal of the Achipeligo, Conrad Tytali and Armand Trianoma are talking...)
Conrad:
"I agree! Pralix and her sister were correct about the Grugach and I'm still impressed with their foresight when they founded this cabal and picked on Davnallius. And I'm convinced that house Flambeau will never figure out our involvment in the death of their unimaginative delagate to that little kerfuffle. What I'm concerned about is that we have allowed Ex Misc to select weak leaders at Cad Gadu [serf's parma]. The first one I understand, but I'm wondering why our group hasn't supported The Scot in his efforts."
Armand:
"Patience, Conrad. This is why am here. Ex Miscellanea is back up to strength and it is time to jolt the Order back into fighting trim. We need to engineer a Wizard's war between the Primus and The Scot and I think we have just the means. Now, I've taken the liberty of laying some groundwork..."
I, too, am glad to see that Gruagachan once more. I would never call them "hedge wizards", however--anymore than I'd denigrate the Sahirs that way. Both are Gifted traditions. They're just not Hermetic Magi.
Ahem.
Not Hermetic = Hedge Wizard
Very simple equation.