You probably already know this, but the final episode of Columbo — the original NBC series, not the ABC follow-up — aired on May 13, 1978.
There were 45 episodes, if you include the 1968 and 1971 TV movies. You can read all about them in Mark Dawidziak’s absolutely indispensible 1989 book, The Columbo Phile. It’s not really a “making-of” book, although it does contain plenty of behind-the-scenes goodies. It’s more like a tribute, a hymn to the show written by someone who is obviously a great fan.
(By the way: if anybody knows where I can score an affordable second-hand copy, please let me know.)
William Link, who created the character with Richard Levinson, has written The Columbo Collection (2010), which features brand new stories. I haven’t read it, but I’m awfully keen to.
In 1981 Levinson and Link published Stay Tuned, a very interesting look at their various television projects — they also did Mannix, Murder, She Wrote, and several very good TV movies — that includes a section on Columbo. Like The Columbo Phile, it’s out of print, but if you’re a fan of the raincoated detective, it’s a must-read.
Also must-reads are the Columbo novels written by William Harrington. There are half a dozen of them, with titles like The Glitter Murder and The Hoover Files, and they’re not adaptations of episodes of the show. They’re original mysteries, with new stories, new crimes, and new twists. They’re also exceedingly well written, almost as good as the show itself. (I say “almost” because Columbo without Peter Falk, as good as it may be, is still not quite Columbo, if you see what I mean.)
The Harrington novels were written in the 1990s, and they’re pretty easy to find. I highly recommend them. I also suggest you check out a handful of novels published in the seventies by MCA Publishing. They’re a mixture of novelizations and original stories, and they’re…interesting. (I’m trying to be diplomatic here.)
Even though some of them are based on actual episodes from the series, the books simply don’t feel quite right. Any Old Port in a Storm (1975), for example, is based on a very good episode — it’s the one with Donald Pleasence as the murderous winemaker — but it’s a poor novel. It reads like somebody translated the script into prose form but had no understanding of the material.
The last Columbo movie aired in 2003. It’s not likely there will be more. And, much as I love the character, I have to tell you: if anybody suggests, even whispers, the possibility of recasting the part, I’ll have some very stern words for them.