I first read about Dog Days in a review at SF Site. Luckily the library had a copy although I probably will be buying my own. This book grabbed me by the throat and I couldn't put it down. It's been a long time since I've been kept up turning pages until around midnight ... and I'd forgotten how good it felt to be interested by a compelling story.
Mason's forte is improvisation. His talent makes him a good jazz musician though if he weren't too lazy to practice he could be a great one. Likewise his talent makes him a good improvisational magic practitioner though, again, if he practiced he could be great ... and I'm not talking about pulling rabbits out of a hat. With Lou who is, for lack of a more precise term, a magical dog-ish companion, Mason makes out ok and enjoys his life.
Until, of course, increasingly stronger magical attacks begin on his life. This sends him to consult his mentor, Eli, and we then become introduced to more about this universe's construction of magic and the people who practice it in San Francisco. As we would expect the story builds to the climax of Mason and Lou versus the evil magic user who is perpetrating some truly heinous crimes for a number of very bad reasons.
Levitt knows how to write a story that keeps the reader on the edge of his seat. Even though Mason might sound like a slacker, this story is the beginning of a series. From Mason's reaction to hearing true assessments of his character, lack of ambition, and potential, we can see that there may be changes taking place over time as he reevaluates priorities. Lou is a lovable character, partially because of how fond Mason is of him and that is another point in Mason's favor.
This is something along the lines of the early Harry Dresden books by Jim Butcher and I look forward to reading the sequel.