This note was last modified Wednesday, 15-Jun-2016 13:59:17 PDT.
This note contains spoilers for the series.
Could also be thought of as the "Lucas Davenport" series, he's the central character. Follows him from the Minneapolis police through the BCA, with a tiny time off in NYC at one point. Just now (book 26) he's quit and joined the Governor's campaign staff in his run for the Presidency.
These, especially the earlier ones, are quirky and more interesting than I'd expect. Davenport has a sideline developing tabletop wargames, and then computer wargames, and then computer simulations of emergency call centers, all of which make money (I know too many game designers to take that seriously, but it's amusing). He has a play-test group that includes a nun he's known since they were children, which is slightly reminiscent of the group in John M. Ford's The Scholars of Night (no reason to suspect any connection that I can see).
Davenport is an ambiguous character in many ways. He's not a totally firm believer in the rule of law. In one early book we see him carefully setting up planted evidence to frame a person he's absolutely certain is guilty (but without admissable evidence. He doesn't need to use it, since he pushes the legitimate investigation and finds actual evidence and uses that; but he was willing to, planning to. He also gets into some doubtful sexual relationships with people he meets on the job.
On the other had, he actually grows and develops. By book 25, where I am as I write this, he has a wife he's faithful to and two children with her plus one adopted child, plus a daughter by a previous liaison that he helps support and is friends with. He's still not an absolute straight-arrow, but he's still very careful about being as honest as possible and doesn't jump to conclusions and do bad things based on that.
Many of Sandford's other books, notably the Virgil Flowers series and the Kidd series, take place in the same universe (Flowers works for Davenport at the BCA, and Davenport calls on Kidd as an art consultant at least once).
The books are largely set in Minnesota. Sandford apparently dislikes the Minneapolis City Hall a lot (I think it's a great building). The books set in the Twin Cities seem weirdly lacking in any sense of place to me. I didn't notice this until I came to books set in the outer reaches of Minnesota, which seem to come with quite a strong sense of place. Sandford was a reporter for the Pioneer Press for a while before making it big in fiction, and lived here for a good part of the writing career, so it's not that he doesn't know the area.
He's a photographer as a hobby; I met him online at The Online Photographer, which I read regularly, and have met him a few times in person, and he has become good friends with my good friend Ctein.
He also collaborated with Ctein on the SF novel Saturn Run.