Lumen Ann Pierce is a fictional character portrayed by Julia Stiles in the Showtime television series Dexter, season 5. Lumen is introduced in the third episode as a survivor of rapist-serial killer Boyd Fowler. She remains for the rest of the season, and leaves following the season 5 finale, "The Big One".

Julia O'Hara Stiles is an American actress. Born and raised in New York City, Stiles began acting at the age of 11 as part of New York's La MaMa Experimental Theatre Club. Her film debut was a small role in I Love You, I Love You Not (1996), followed by a lead role in Wicked (1998) for which she received the Karlovy Vary Film Festival Award for Best Actress. She rose to prominence with leading roles in teen films such as 10 Things I Hate About You (1999), Down to You (2000), and Save the Last Dance (2001). Her accolades include a Teen Choice Award and two MTV Movie Awards, as well as nominations for a Golden Globe Award, and Primetime Emmy Award.