After five decades of spacecraft exploration of the Solar System, the origin of two moons of Mars, Phobos and Deimos, remains a perplexing mystery. Are they a) captured asteroids, b) remnants of Mars’s formation, or c) reaccreted impact ejecta from Mars? These small bodies lie at the crossroads of a wide range of outstanding issues in solar system research, and elucidating their origin tests our understanding of planet formation and solar system evolution, including the question of how water and organics became available on Earth. Meanwhile, Phobos and Deimos are emerging as key stepping stones in the future human exploration of Mars. Dr. Lee's talk will cover the history of our efforts to understand Phobos and Deimos, and new prospects in their exploration.