Gary Zank is a prominent theorist in the physics of space plasmas and an exceptional leader, administrator, and educator. He has leveraged these qualities to support the heliophysics science community and advance the field of space plasma physics. Gary was elected to the National Academy of Sciences in 2016. His scientific research has impacted many of the key areas of the field. He has performed pioneering work on solar wind and its interaction with the interstellar medium forming the global heliosphere. His work has particularly clarified the intricate physics of multicomponent plasmas of the distant heliosphere. He also developed some of the first numerical models to study intense solar energetic particle events, the foundations of which are currently used in today’s state-of-the-art modeling. He has significantly advanced our understanding of high-energy particle transport in the heliosphere, including the nature of turbulent magnetic fields in the heliosphere, and the physics of astrophysical shock waves and particle acceleration. He has authored over 650 publications having more than 30,000 citations and an h-index of over 90. In addition to his impressive scientific achievements, Gary has been a tireless advocate of our field. He has served on some of the community’s most influential panels and committees, helping to ensure the continued success of our field and shape its future. He has served in editorial roles for numerous journals, including the Astrophysical Journal for the past 13 years. His persistent effort to create a thriving space physics department at a U.S. university has succeeded in the formation of the Department of Space Science at the University of Alabama in Huntsville. The department offers M.S. and Ph.D. degrees in space science and currently has 11 faculty, 1/3 of whom are women, and 44 graduate students. Gary is an exceptional educator, having supervised 17 Ph.D. students and 29 postdoctoral research associates; wrote a graduate textbook on transport processes in space plasmas; and developed five summer outreach programs, aimed at research experience for undergraduate and graduate students. He has organized numerous science conferences and seminars, including the extremely successful Annual International Astrophysics Conference series for over 20 years. Gary Zank exemplifies what the AGU John Adam Fleming medal is meant to honor. —Joe Giacalone, University of Arizona, Tucson, Arizona

For his many contributions to our understanding of the physics of the heliosphere and its interaction with the interstellar medium.