The Mage: the Awakening core book is horrible. It’s dry, confusingly written, and devotes all too much page count to rotes (i.e. “hardcoded” spells, as opposed to freeform ones). I’ve been told that Mage has potential as a game, but you really need to read some other sourcebooks to see that – and Tome of the Mysteries is the most often quoted “must-have” book. I can see why.
The book is a lengthy examination of how magic works in this game, with emphasis on freeform magic use. We’re given a system for categorizing various effects, giving the GM and the players guidelines at how many dots are needed for different things. There’s also a lot of discussion on how magic works in general (in the game, that is), including how it feels to cast it and other “fluff” but very important things. Given how dry the core book is, you might think that a book on the mechanics of magic to be a tedious read – but it’s actually not, most of the book is very well written and illustrates at time obscure points and effects in an engaging fashion.
The book ends with some more esoteric stuff, like use of Abyssal magic and the possible powers of Archmages. The Abyssal stuff is fun, a classic “get power fast, but at cost” trap with lots of story potential. The Archmage stuff is more abstract and not really all that useful, but at least it’s something.
Overall, this is a fantastic book for anyone actually thinking of running or playing in this game. It lets the players use freeform magical effects without too much GM headache, and provides a very nice conceptual framework for talking about them… and one that is also usable as an in-game subject of discussion.
Still not really sold on this incarnation of Mage, but this book does improve on the core book a lot.
This book used to be out of print and very hard to find at a reasonable price (annoying for such a “must have” book), but it has recently been entered in White Wolf’s “print-on-demand” program and is now available directly.