Diane Keaton, who joined the ranks of movie motherhood last in "Baby Boom," portrays a parent again in "The Good Mother," based on Sue Miller's novel of the same title. Leonard Nimoy will direct the drama for Disney's subsidiary Touchstone Pictures. The cast includes Liam Neeson, Jason Robards, Ralph Bellamy, Teresa Wright and James Naughton. Keaton plays a recently divorced mother struggling to balance her devotion to her young daughter against her attraction to an ardent suitor, played by Neeson.