"Magelight or Magefire is so common among MAGIC USERS that it is probably what an APPRENTICE Wizard learns to do on his first day. The operator simply thinks, and a small ball of bluish or white light appears.... It is otherwise not good for anything much, but it would be nice to be able to do it."
So says Diana Wynne Jones in The Tough Guide to Fantasy Land.
Peter Grant, the hero of Ben Aaronovitch's series beginning with Rivers of London, is a bona fide APPRENTICE Wizard - he had to take an oath and everything - and the first thing he learns to do is make a werelight, which is the same thing as Diana Wynne Jones' magelight. In his case, however, it takes him four hours of practice a day for a month before he can do it, and then he burns his hand the first time. He also has to learn Latin, because all the books of magic back to 1775 when Newton codified the practice of magic (in between inventing science and reforming the Bank of England) are written in Latin.
I like Peter a lot. The story is told in the first person, and he has a nice line in snarky comments that had me laughing out loud on occasions. He's also pretty good at being quick-witted in dangerous circumstances.
The other thing I like a lot about the book is The Folly - a sort of gentleman's club for magicians, though at the moment (for reasons at present shrouded in mystery) the only occupants are Peter, his Master/Inspector Nightingale, Molly the not exactly human maid, and Toby the ghost hunting dog. Charles de Lint has a similar big house with lots of unusual occupants (sometimes artists and sometimes more esoteric guests) in his Newford urban fantasies. I'd love to live in a place like that, with three libraries, and good food - I suppose the Tardis is another similar place (when you get beyond the console room to the library and swimming pool and so on) and Ben Aaronovitch has been a Doctor Who writer.
There's another Doctor Who writer who is writing a broadly similar series about police dealing with magical crimes in London - Paul Cornell, whose first book in his series is London Falling. He's also a very good writer, but I found his characters much less likeable, and the world they live in rather more bleak, than Rivers of London. Terrible things happen in Ben Aaronovitch's world too - people's faces fall off in graphically horrible detail, for instance - but there's a lot more humour.
I'm looking forward to the rest of the series.