Photodynamic therapy has become a safe, effective, and painless option for treating actinic keratosis. In the introduction to this 3-part series on PDT, Dr. George Martin, dermatologist and founder and program chairman of Maui Derm, Maui, Hawaii, introduces three of the world's leading authorities on PDT who help to dispel the misconceptions that PDT is a painful, expensive, and ineffective treatment.