Maggie Siff (born June 21, 1974) is an American actress. Her television roles have included department store heiress Rachel Menken Katz on the AMC drama Mad Men, Tara Knowles on the FX drama Sons of Anarchy, and psychiatrist Wendy Rhoades on the Showtime series Billions. She has had roles in the films Push (2009) as Teresa Stowe and Leaves of ...