Steven R. Jefferts (M'01) received the B.S. degree in physics from the University of Washington, Seattle, in 1984 and the Ph.D. degree in atomic physics/precision metrology from the University of Colorado, Boulder, 1992. His Ph.D. dissertation involved the ultrahigh-precision mass spectroscopy of light ions.,Since 1992, he has been with the National Institute of Standards and Technology (NIST), Boulder, where he was an NRC Postdoctoral Fellow working on laser-cooled trapped ions. Since 1994, he has been a permanent employee with the Time and Frequency Division, where he leads the research group developing and operating cesium fountain primary frequency standards.,Dr. Jefferts received the Edward Uhler Condon award in 2001, a Department of Commerce Gold Medal in 2004, and the Arthur S. Flemming Award in 2005. He was also the IEEE-UFFC Distinguished Lecturer from 2003 to 2004.