The first three Dirty Harry movies came out between 1971 and 1976. Then, there was a hiatus of seven years, until 1983's Sudden Impact. With the franchise dead going into the '80s, Warner Books decided to begin a series of media tie-in novels (although I doubt they were called that at the time) featuring the eponymous maverick cop and his Smith & Wesson .44 Magnum. The series ran from 1981 to March of 1983, nine months before Sudden Impact was released. The series was written by two authors; Ric Meyers (who wrote the Ninja Master books) and Leslie Alan Horvitz, a writer I'm unfamiliar with. Meyers apparently wrote #'s 1, 3, 5, 8, 9, and 11.
The first book in the series, Duel for Cannons, opens with the line, "Boopsie's head exploded". The unfortunate Boopsie is a guy in a cartoon-figure suit at a knockoff Disney World-esque theme park in California. Boopsie is killed by a gunman who then gets chased by an off-duty San Antonio sheriff visiting the amusement park with his family. The sheriff gets drawn into a running gun battle with the shooter, and is eventually killed. Of course, the deceased is an old friend of Harry Callahan's, and Callahan doesn't take kindly to his friends being killed, even less so when the killer makes it look like the death was actually the sheriff pulling off a mass murder/suicide.
Although everyone else almost immediately dismisses the inconsistencies in the case, Harry pursues the evidence, and eventually uncovers a shadowy killer who seems to be trying to draw Harry to San Antonio. Eventually Harry goes there, and discovers that H. A. Striker, a wealthy business magnate, essentially runs the city, owns the cops, and gets to do whatever he wants. Striker had been opposed by the Sheriff, and one of his underlings, a tactically brilliant investigator named Nash. Harry teams up with Nash to try and bring down Striker, who is actually furious that the assassin - a .44 Magnum-loving killer named Sweetboy Williams - lured Harry to San Antonio. Striker tries to get Harry arrested or driven off several times, only to get foiled on every occasion.
The story culminates with a ton of gunplay, as Striker tries to use a captured Nash as bait to lure Harry into a place where his bought cops - or Williams - can kill Harry. There's a ridiculous amount of gunfire and stuff getting smashed / shot / blown up, and although the killing isn't too gratuitous, at least one bad guy gets his head "blown clean off". I don't want to give away the details - there are a few twists and turns - but the ending is pretty satisfying, although the middle third of the book does sag a bit, and I found the whole plot a little hard to believe. With the police corruption looking SO blatant and rampant in San Antonio, and with the amount of evidence Nash gathers on Striker's doings, I don't see how he couldn't have just passed the information on to the FBI or some other, larger agency.
But overall, I found Duel for Cannons to be great fun. I've recently re-watched the first three Dirty Harry movies, and this book definitely references his filmic adventures extensively. One minor deviation is that DiGiorgio, an inspector who appears in all three earlier movies, is alive in this book, while (SPOILER) he's killed midway through The Enforcer. I suppose he was too good a secondary character to leave dead and buried, since his chubby, laid-back persona is a great counterpoint to Harry's belligerent, wound-up personality. There's also enough time spent in San Francisco dealing with punks and criminals there, that I'm looking forward to later stories taking place in the city itself. Meyers is able to capture and reproduce a lot of Harry's personality, and I can easily hear Eastwood speaking the dialogue in the book with Harry's typical laconic delivery.
It looks like Amazon has most, if not all of these books available for a somewhat reasonable price used, assuming you're not looking for mint condition specimens. I've already ordered the second book in the series, and I'll review it as soon as I can.