What is the author's style in Always Running: La Vida Loca, Gang Days in L.A by Luis J. Rodriguez?

The book is written in first person from Luis's perspective. The majority of the book is written in past tense, but the author lapses occasionally into present tense, as Luis tries to explain something that isn't really part of the story line but is an important part of his life. For example, the story about Jose and the guitar comes after Luis describes meeting Vivian and just before a scene involving a fight at his high school.