Dr. Bookless received his Ph.D. in physics from the University of Wyoming in 1980. For the next 32 years, until 2012, he was a senior physicist at the Lawrence Livermore National Laboratory. He worked on a wide range of nuclear security topics as the Deputy Associate Director for the Lawrence Livermore National Laboratory nuclear weapons program and Associate Director for Safety and Environmental Protection, culminating with a two and a half year assignment as a senior advisor to the Administrator of the National Nuclear Security Administration (NNSA) from 2009 until 2012. As senior advisor, he received NNSA awards for his work supporting the 2010 Nuclear Posture Review and the New START Treaty. From 2012 to 2015, he was the Assistant Laboratory Director for Policy and Planning at the Brookhaven National Laboratory, before retiring in 2015.