Black Friday is, of course, Dr. Jekyll and Mr. Hyde in modern clothing and with a "scientific" explanation, and it is probably no coincidence that Robert Louis Stevenson's classic tale was being readied at the time by MGM as a vehicle for none other than Spencer Tracy. Although they didn't employ anyone of that caliber, Universal had both Boris Karloff and Bela Lugosi on the payroll and much have been said in recent years about the studio's failure to bring the horror icons together in Black Friday. For the more casual viewer, however, such trivia means little, especially since the real star of the thriller is Stanley Ridges, a veteran character actor who earned the role of a lifetime playing both the kindly and learned Professor Kingsley and the homicidal gangster Red Cannon. Ridges is a revelation, and, like Tracy, attempts the difficult task of creating two very different characters with little to no makeup. To Ridges' eternal credit, he succeeds where Tracy would fail.