The Mary Tyler Moore Show endures because its timeless comedy is drawn from the wellspring of its fully drawn characters, who were allowed to grow beyond one-note caricatures. Mary's best friend, Rhoda (Valerie Harper), who was in danger of becoming this series' Sally Rogers, really blossomed this season. In "Rhoda the Beautiful," the slimmed-down Rhoda is empowered to enter a beauty contest, and in "My Brother's Keeper," she catches the eye of Phyllis' (Cloris Leachman in an Emmy-nominated performance) brother, which devastates Phyllis, setting the stage for yet another disastrous Mary Richards party (and a dénouement that must have been daring in 1973). Wise-cracking Murray (Gavin McLeod) reveals new depths in "Murray Faces Life," in which he sinks into depression after hearing that a former college classmate has won the Pulitzer Prize. Even Ted manages to surprise. In "Operation: Lou," a hospitalized Lou Grant finds a new appreciation for Ted, who graciously and uncharacteristically, presents him with an expensive bottle of scotch. Moore, Harper, and Knight were each honored with Emmys this season. Joining this august core ensemble is Georgia Engel as Georgette, who makes a delightful first impression in "Rhoda Morgenstern: Minneapolis to New York." Even hard-boiled Lou softens in her presence. "You're a real cutie, you know that?" he tells her in "The Georgette Story." Despite Lou's insistence to the contrary in "The Good-Time News," The Mary Tyler Moore's job was to make people laugh. But it could also be surprisingly moving, as in the laugh-free dramatic climax of "Remembrance of Things Past," in which Mary is reunited with an ex-boyfriend (Joseph Campanella), who has broken her heart in the past. This three-disc set contains no extras, but any of these episodes can take a nothing day and suddenly... well, you know the rest. --Donald Liebenson