Unless this new Spenser book by Ace Atkins is based on an outline by Robert B. Parker, I can't understand why a Parker/Spenser fan would want to buy it.
So far, the one and only author of the Spenser series has been Parker. Bringing in a new author to continue the series seems a bit crass.
I know that there are hundreds of Sherlock Holmes stories by authors other than Conan Doyle, but the last line of Sixkill seemed like a farewell from the author to his fans. It was as though he knew that the end was near.
"I got in my car and I drove west."
Good bye, Spenser.
Your father was a good man.