Two actresses duplicate the impressive professional achievements of their characters with Collected Stories, the PBS adaptation of Donald Margulies' two-woman drama about a literary apprenticeship gone sour. TV and stage veteran Linda Lavin gives a performance that's nuanced down to the wrinkle, as might be expected from a seasoned pro who's honed her craft beyond the sitcom realm. But the real surprise here is Samantha Mathis, a teen actress matured into a true thespian, who goes toe-to-toe with that grand dame and ably executes her share of a demanding dialogue. Both portrayals splendidly dramatize the slippery plate tectonics of a relationship shifting from its former balance to a new, uglier dynamic. As the straightforward definition of their roles and positions of strength within the friendship blurs, there are no simple answers, and the collaborators explore this displeasing reality without blinking. Though it's a consummate stage production, set only in the mentor's apartment and featuring only two performers, Collected Stories translates well to the screen because of how the actresses and director Gil Cates Jr. add intensity to Margulies' engrossing words. Margulies dissects the craft of writing from specific details to overarching theories, and in turn engages rich issues of intellectual property, personal privacy, and the hazy line between theft and homage, fiction and non-fiction. The result is a gift for both those who love words and those who love their dramatic interpretation.