Yes, Barbara, I have patiently purchased every single Peter Robinson (the author) book every year when a new one comes out in paperback, because once years ago I read a rave review of him. Like so many other books I buy and put on my shelves, the Robinsons are each carefully numbered on the outside with my stickers, so that I can both keep them in proper order on those shelves and know which order to read them in. I must confess, with so much on hand to read, I completely neglected Robinson until those films began to appear on PBS. By the way, the DCI Banks in the films does not look AT ALL like the one portrayed in the book, but I have become quite used to and fond of him. Anyway, starting with my liking the films, I started reading the actual books, and I have now completed NINE (9) of them and have number ten (In A Dry Season) ready and waiting on a bedside stack. Still, there is so much ELSE waiting its turn to be picked up and read, that lord only knows when I will finish the series. I have TWENTY (20) books, so far, and yes, he is still writing. They are quite good. Not outstanding, like my darling Josephine Tey; but quite engrossing and I am very fond of DCI BANKS!
Oh, and to answer your question, the films DO follow the books quite closely. Sometimes they have to tweek them a tad, but all filming has to do that.