The opening fiction is a tale of a youngster growing up in a house where one parent is Awakened and the other is not, and worse, finds it difficult to accept. Sad truths... perhaps some one of your mages might have to face, or have as part of their background.
The Introduction explains the underlying concept of this book: magic as Art: a craft that must be studied, learned, honed, thought about and practiced... not mechanical cause and effect. Indeed magic often seems to have a will of its own. Presenting a scheme to classify magic in terms of the elements, it's at pains to point out that the classifications are more philosophical than anything else. Each element has associations with emotions and capabilities, and it is these that are reflected by the magic grouped together under it. In summary, will comes under fire, for intellect air is the proper element, with water for feelings and emotions and earth for the manifestation of ideas. Not everyone thinks this way, of course. Some mages like to visualise a temple with many halls, visiting different ones depending on what they are doing. Others claim that there are various fields of study within the whole that is magic - just as the academic study of say, history, might include the study of different periods, different places, or themes such as warfare or religion. But here we stick to the elements as a framework, with this book serving as a toolbox for how to go about using magic.
Chapter 1: The Way of Fire - Making Magic looks at that exciting area of how to devise your own spells. If creative thaumaturgy is your thing, this chapter will light your fire. The element of fire is associated with intuition, imagination and the higher will, just the tools you need to come up with innovative new spells. Here you can read about the 'rules' that make magic work: the Thirteen Practices, spell Aspects and the practicalities of creating a new spell.
Next, Chapter 2: The Way of Air - Spell Lore explains the look and feel of magic, how to describe what's going on, what can be felt and seen as a spell is cast. Seek inspiration here when you want to get creative when telling people what is going on when the magic starts to fly. There are lots of new spells here as well.
Then Chapter 3: The Way of Water - Magic and Being is about how magic interacts with culture and society, and as an extension of that, how mages get on with day-to-day life, and what sort of beliefs they might hold. There's also a discussion of the ethical aspects of magic (quite entertaining given that I teach the ethical aspects of computing in real life!). These are the sort of questions that the modern mage ought to wrestle with.
Chapter 4: The Way of Earth - Magic Manifested presents spells which are used to enchant items. There's also a look at alchemy and an array of salves, sprays and other substances that can be made with this craft, and a fair bit about soul stones.
Finally, Chapter 5: The Way of the Void - Greater Secrets takes you down paths best trodden with caution if at all... this is the Storyteller chapter and includes all manner of things from running antagonist spell casters to the legendary capablities of archmages and the dread Abyssal Watchtowers (which if you haven't heard of, you are probably very lucky!). Your NPC mages need to be as rounded, as knowlegeable as any player-character, but a bit of careful planning can make this less arduous than it might sound. There are lots of helpful hints and tips here.
Ending with a comprehensive spell index, this is a mage's vade mecum, a reference book or manual. OK, you don't need to read it to play an effective mage... but if you do study its pages, it will give your mage and his magic considered depths, a greater understanding of the Art he practices.