Even a series this broad can't fully limn Tracy's prolific career. (He made more than 70 films.) Thus the terrific "Boom Town" (1940), with Clark Gable and Claudette Colbert, isn't included, nor is the biopic "Edison, the Man" (also 1940).
WSJ: Spencer Tracy: That Natural Thing | He Made a Career Out of Acting Ordinary | By David Mermelstein