A very good, and above average, Columbo episode. This is caused by that it makes small variations from the classic scheme. The motive of the murder isn't present at the beginning, which is something, that really improves the movie. Columbo is playing up against Dr. Eric Mason (nicely played by Nicol Williamson), who doesn't loose his temper as much as the characters that Columbo previously met.
The third main character, Joanne Nicholls, should have a special mention, since she is not only played extremely well - by Kim Cattrall, later of "Sex And The City" fame (however her role in this movie is the complete opposite, a true romantic who has her teddy bear as her true companion) - but also that her unbalanced character adds well to the movie plot.
And ad with that, some great incidental music, good directing spots (particularly in a wordless sequence with Columbo and the dog trainer), a generally good script(rarely have I laughed so much in a Columbo movie, and the many references to old movies - particularly Citizen Kane - and psychology are well-put and well used), and that Peter Falk seems in top shape makes it a great movie, and a Columbo classic.