Any episode of "77 Sunset Strip" written (or co-written) by Roger Smith (as Jeff Spencer) is first-rate, and this one is no exception. As another reviewer pointed out, the relationship between the police and the private detective is antagonistic in virtually every series of this genre, but not here. In fact, Jeff Spencer is a personal friend of the police lieutenant who, in this episode, comes to Jeff to ask for his unofficial help. The police are getting nowhere in finding who the psycho serial killer is responsible for the brutal slayings of several young Beverly Hills beauties, and "The Common Denominator" explores in methodic detail how Spencer, using his keen intelligence in discovering and following up on clues, tracks down the murderer (and I'll wager you'll never come close to guessing the identity of the culprit). The episode is filled with genuine suspense and shudders (the depiction of the killings is pretty graphic for 1961). And when Spencer is finally able to tie the slayings together when he realizes all of the victims spoke with French accents, you can be sure he'll engage his agency's gorgeous French secretary as a decoy to trap the killer. (The show's ardent fans will recall that in one of its first episodes, Roger Smith and Jacqueline Beer fell in love and he asked her to marry him!)
No spoilers from me,just my appreciation for Mr. Smith's first-rate screenplay which is so much more than a mere whodunit (albeit a dandy one). What truly makes it shine is its nuanced character study of the very real friendship between Jeff and his policeman friend, and also between Jeff and his lovely, intelligent secretary. "77 Sunset Strip" was always filled with the most beautiful young starlets of its time, but, for me, Jacqueline Beer was the most delectable actress to ever appear on the series. The chemistry between Ms. Beer and Mr. Smith is so palpable that you won't even miss the absence of Efrem Zimbalist Jr. and Richard Long (Edd Byrnes has two very brief scenes, and that's it for Kookie and his comb).