How magic works
We had a number of conversations during the first few weeks of developing the plot and writing the first couple of chapters deciding exactly how magic should function in our world. Would wizards require wands or magic words? Would they spend time memorizing complex spells? Could anyone learn magic or were you born with the power and had to learn how to control it? How would we limit magic to prevent the wizards from being too powerful and completely taking over the world? Would all of the races have wizards, or only the humans?
After a lot of discussion we decided that wizards wouldn’t memorize spells or require magic words or magic wands. Instead, magic requires a deep understanding of what you want to accomplish and how you would make that happen. Magic is also limited by the wizards natural ability. Many spells take both a physical and magical toll on the spell caster, so a big spell may knock out the wizard or even kill them, and there is still no guarantee that the spell will work as imagined or even do anything at all.
As Frank said the other day, we tried to develop magic in such a way that it both leveraged and obeyed physical laws. We also tried to make each wizard use spells that match their personality, experience and ability.