When M20 broke Focus into Paradigm/Practice/Instruments, I was glad it made explaining how to build a Mage's beliefs and magickal style so much easier. Along comes Prism of Focus, which added a couple of extra puzzle pieces that I didn't know that I needed. Suddenly the process wass even more clear and smooth.

The first win for me was how it improved the character creation process. You can start with the new Tenets that informs the Paradigm that fits best with, or at least is close to, your core beliefs. (Of course, you could instead start with Tradition and pick one of their Paradigms, which gives you associated Tenets.) Then those Tenets narrow the list of Practices that most easily work from those beliefs, causing that choice to be made from a shorter list. Practices have a (again smaller) list of Instruments. Practices also have associated Abilities, similar to how Do is presented in M20, and they make sense for using that Practice's Instruments. The details in this book makes explicit the connections between all of these pieces.

Where Paradigms are wide and cover many different beliefs, Tenets are narrow and can directly guide some roleplay situations. Practices are now ranked with dots in a way that integrates them with the casting process, Sanctums, and Reality Zones. They are such elegant solutions the to parts of the game that were previously rule-less.

My game is a long way off from using the high-level options, but everything presented makes sense and promises to add a lot of fun to kind of game.

I consider this book an essential add-on the the M20 corebook, for both Storytellers and players, regardless of experience.