Kaibab Unbound (The Iron Druid Chronicles #0.6) by Kevin Hearne published in 2011
A short story in The Iron Druid series that occurs two weeks before the events of the first book.

How was it? The short-story really hammer in the fact that Atticus is old 2100 years old and in hiding. Two facts that were already touched upon in the past two shorts [1, 2], except here some lights is shed on who he’s hiding from and why. The world building continues though, as we’re getting acquainted with witches. We also learn about one more – a hound – of the four animal shapes Atticus can bind himself to.