Maggie Siff is an American actress. Her most notable television roles have included department store heiress Rachel Menken Katz on the AMC drama Mad Men, Dr. Tara Knowles on the FX drama Sons of Anarchy for which she was twice nominated for the Critics' Choice Television Award for Best Supporting Actress in a Drama Series, and psychiatrist Wendy Rhoades on the Showtime series Billions. She has also had roles in the films Push (2009) as Teresa Stowe, and Leaves of Grass (2010) as Rabbi Renannah Zimmerman. She starred in indie film A Woman, a Part (2016) and had a minor role in the drama film One Percent More Humid (2017). She is the television spokesperson for the robo-advisor service Betterment.