Dirty Harry lets the bullets fly when a Texas lawman friend is killed by an assassin in Duel for Cannons, the first in the 80s paperback spin-off series from the films, .
The novels are all credited to "Dane Hartman," but this is by Ric Meyers, who has written all kinds of things from non-fiction about martial arts to comic books to various paperback genres. Various others tackled Dirty Harry under the Hartman name as well, but I was glad to find this was by Meyers, whose work I have read before.
I was very mixed about Duel for Cannons; there were a lot of clever touches, like a vegetarian villain, and some set pieces around San Antonio, but there was a lot of dumb plotting, like a guy picking up a prop gun on a movie set and thinking it had real bullets.
There is also sort of a general unpleasantness about it, with Dirty Harry solving even modest conflict by shooting people dead. Overall, though, Meyers writes an accurate Dirty Harry and sets it in the world of the films.
I know these paperbacks are somewhat collectible, but this one I bought for a dollar at a junk shop, read in a single day camping, and left at a Little Free Library. For undiscriminating fans of the movies.