Thank you very much, Pete. Now my Sunday evening has closure.

Well-done, Pete!

The ending seems to confuse a lot of people -- we've seen lots of questions like "How does the spoiled wine prove anything?" -- so I'll add a couple of things about that clue.

The spoiled wine may not "prove" that Adrian was the murderer, but it does tend to show that the cellar got overheated, as itf the climate control had been off during the heat wave (while Adrian was out of town). The key thing about that, is that the cellar is air-tight, so when the AC was off, the cellar became a good place to suffocate. Columbo had intuited this very early, comparing the wine cellar to the suffocation-chamber in Poe's story ("The Cask of Amontillado"). And, due to other little clues, he was already looking for a likely place -- NOT the ocean -- for the victim to have died from lack of air.

But as Pete summed-up, the point is not that the wine is, um, air-tight proof -- it is the final leverage for Columbo to push Adrian, who already felt trapped, into confessing.

As much as anything else, it was Adrian's dread of marriage that did him in -- but Columbo also knew this about Adrian, and twisted the screw by telling him how important the secretary's alibi was in exonerating him. So this is another case where Columbo solves the murder using his gift of insight into the suspect's psychology.

A true classic episode. And whenever I don't like a certain wine I look at my wife (not in public of course, lol) and say: "Everything is wrong! How could you serve me this LIQUID FILTH!

This is one of my favorite episodes, and I appreciate the discussion on this thread. The question I still have is, "What did Columbo do to Adrian that made him so apologetic on his call from the secretary's house?" Colubo tells Adrian that he was happy that Adrian did not report him - but to me Columbo did not badger Adrian at all. I keep thinking that for some reason my DVD does not contain some important scenes. I know that Columbo wanted to get Adrian to the restaurant to complete his plan - but he might have just invited him without the apology.