A planetary scientist in the Space Science Division of the National Aeronautics and Space Administration’s Ames Research Center since 1982, Christopher P. McKay has devoted his career to the search for extraterrestrial life. His interest in the subject that became the focus of much of his research dates from the fall of 1976 when two Viking spacecraft landed on the surface of Mars and he read, with growing excitement, the published interim reports of the experiments underway to detect metabolic activities on Earth’s cold, dust‑covered solar neighbor. Since then, when many scientist concluded Mars was barren, microbiologists have developed a treasure trove of tools for detecting microorganisms, and Dr. McKay has argued that microbial life might still exist on the Red Planet. A graduate of Florida Atlantic University, where he majored in physics, he had just begun graduate work in astro-geophysics at the University of Colorado when the first probes set down on the Martian surface. He completed a Ph.D. in 1982 and immediately became involved in research in Mars-like environments on Earth. Dr. McKay’s initial field work was in the dry valleys of Antarctica as a scientist with Florida State University’s Cryptoendolithic Microbial Ecology Research Project. He was subsequently a research diver in the 1986 Antarctic Lakes Project and a member of expeditions to the Siberian arctic permafrost regions in 1990-91 and 1994, the National Geographic Expedition to the Gobi Desert of Mongolia in 1991-92, the NASA/United States Geographical Survey Expedition into the Lechuguilla Cave in New Mexico in 1994-95, the McGill University Expedition to Axel Heiberg Island in the Canadian Arctic in 1995-96, and the NASA Expedition to the Atacoma Desert in Chile from 1994 to the present. He also has made several expeditions to Negev Desert in Israel. Dr. McKay served as co-investigator on the Huygens probe to Saturn’s moon Titan in 2005, the Mars Phoenix lander mission in 2008, and the current Mars Science Laboratory mission. A fellow of the International Society for the Study of the Origin of Life and the American Geophysics Union, he is a member of the United States Committee for the International Permafrost Association and of the board of directors of the Planetary Society. His various honors include the U.S. Antarctic Service Medal, the Urey Prize of the Division of Planetary Sciences of the American Astronomical Society, the Arthur S. Flemming Award given in cooperation with George Washington University, the Planetary Society’s Thomas O. Paine Memorial Award, and five NASA awards, including the 2012 Presidential Rank Award. A member of the board of advisory editors of Planetary Space Science, Dr. McKay is author of some 400 scientific papers and the editor of four books, including (with P. J. Thomas and C. F. Chyba) Comets and the Origin and Evolution of Life (Springer, 1997). He is actively involved in planning for future Mars missions including human exploration.