Peter Grant has come to the end of his two years as a probationary constable with the Metropolitan Police Service, and is about to get his permanent assignment. He desperately hopes to avoid the Case Progression Unit, i.e., the unit that does the paper work so real cops don't have to. His chances aren't looking good.
Then on what would likely be one of his last shifts as a constable on the street, he guards the scene of a seemingly inexplicable murder, he meets an unexpected and potentially valuable witness: a ghost.
This brings him to the attention of Inspector Thomas Nightingale, who heads up a unit Peter had no idea existed. Specifically, Nightingale heads of the unit that deals with magic, ghosts, the undead, and the genii loci of the surrounding area. Nightingale decides that Peter's ability to see ghosts and sense magical residue makes him a promising apprentice wizard--the first new apprentice in decades.
After some hesitation, Peter decides to seize this chance to escape assignment to the Case Progression Unit. It's not long before he's chasing the malevolent spirit of a dead frustrated actor, attempting to negotiate a peace between a god and goddess of the Thames who are on the brink of war with each other, and learning how the Metropolitan Police Service in the early 21st century deals with a nest of vampires.
And of course, there's the little matter of his lessons in magic, and discovering the tricky aspects of doing magic in the presence of modern technology you'd like to continue using afterwards.
Peter Grant is a thoroughly likable character, who loves his city and who is proud of his police service without being either sloppy or macho about it. He and the London he lives in also reflect the complexity and diversity of the 21st century city, not the 19th century city.
I bought this book.