As a splendid sampler of standout episodes from the 20-season history of Gunsmoke, this well-chosen Directors Collection is a bona fide treasure. Fans of the long-running Western series will appreciate the archival care that went into this set: Not only does it provide a comprehensive overview of the series' evolution (from original radio shows to one-hour color episodes from the 1960s and '70s), but it also delivers a priceless abundance of oral TV history in the form of audio commentaries, some recorded by series stars and directors (like Dennis Weaver, a.k.a. "Chester") shortly before their death.