What is the author's style in High Wizardry by Diane Duane?

High Wizardry by Diane Duane is a novel written in the first person perspective. The story is narrated by one character at a time, switching between sisters Nita and Dairine Callahan, who are the main characters of this story. The author switches from one narrator to the other, beginning with Nita. The chapters alternate perspective almost all the way through the novel.