Group Name: The Robert H. MacArthur Award is given biannually to an established ecologist in mid-career for meritorious contributions to ecology, in the expectation of continued outstanding ecological research. Nominees may be from any country and need not be ESA members. The recipient is invited to prepare an address for presentation at the annual meeting of the Ecological Society of America and for publication in Ecology. Alan Hastings of the University of California at Davis is one of the most respected theoretical ecologists working today. He has been a leading force in this field for two decades. He is distinguished both for his research and for his commitment to advancing the basic ecological sciences and their management implications. He has published fundamental papers in population genetics and ecology, made important contributions in metapopulation theory and conservation biology, and brought the full power of sophisticated advances to bear on the solution of applied problems. After receiving his Ph.D. from Cornell in 1977, Dr. Hastings began his professional career at Washington State University in the Department of Pure and Applied Mathematics. Since 1979, he has been at the University of California at Davis, where he is now Distinguished Professor in the Department of Environmental Science and Policy, which he chaired from 1992 to 1998. As a mentor, Dr. Hastings has trained 16 doctoral students and 22 postdocs, and is beloved by those who have worked with him. His contributions to the wider community include service to the Society for Mathematical Biology as President and to the ESA as Chair of the Theoretical Ecology Section. Currently, he is Editor-in-Chief of the new journal Theoretical Ecology, the Theoretical Ecology Series for Academic Press, Co-Editor-in-Chief of the Journal of Mathematical Biology , and serves on the Editorial Board of Mathematical Biosciences . In the past, he has served on the Board of Editors for Ecology and Ecological Monographs and as Associate Editor for Evolution, Oecologia. and Theoretical Population Biology.