Joan Didion is one of our most acclaimed essayists, and her incisive observational gifts and fluid style drive The Year of Magical Thinking. A meditation on the personal fallout of almost inconceivable loss (the sudden death of the author's husband followed by that of her daughter), the play is adapted from Didion's award-winning book of the same title. If it sounds like an unlikely candidate for the stage — a continuous monologue with minimal action — Year as a play builds on the sensation of intimacy and the energy of an actor's live presence that theater can provide. The fact that it's a riveting experience owes immensely as such to Mary Beth Fisher's seamless, subtle performance.