Although some critics felt Close was too refined for a series as gritty as The Shield, she quickly found her place in the show's tight ensemble, earning an Emmy nomination (along with Pounder) and giving Mackey a formidable boss who earns his respect. And while Aceveda wrestles with psychosexual demons resulting from his humiliation in season 3, the high-stakes threat of Antwon Mitchell embroils the Barn in a cauldron of mistrust and political upheaval. More than any previous season, this 13-episode story arc is character-based and internally driven by clashing agendas. Sub-plots run the gamut of neighborhood killings and gang-banger conflict, but as always The Shield also finds room for plenty of mordant wit and tension-relieving sarcasm. Like all previous Shield DVDs, this four-disc set includes informative episode commentaries from the entire cast (including Close) engaged in revealing discussions of their creative process with creator Shawn Ryan and several primary writers and directors. Best of all, the "Under the Skin" documentary is a way-above-average, 60-minute survey of The Shield's day-to-day production, offering plenty of behind-the-scenes footage and eloquent insight about the challenge of maintaining high-quality drama during a fast-paced guerilla production schedule. It's essential viewing for Shield fans and anyone considering a career in television. --Jeff Shannon