Allen Hunt was trained as a physicist in the application of percolation theory to transport in disordered systems. Post-doctoral experience in soil physics, geomorphology, and hydrology acquainted him with a series of difficult physics problems in porous media, particularly those of soil formation and soil processes. Hunt has over 150 refereed publications in the above fields, climate dynamics, and biological sciences in 45 traditionally archived journals, including Nature. He has been a Fulbright Scholar, and a National Science Foundation Program Director. He is currently Professor of Physics at Wright State University. His book, Percolation Theory for Flow in Porous Media (Lecture Notes in Physics, Springer) has gone through three editions in the past 10 years. He has earned teaching distinctions at the local and national levels, and his PhD student, Behzad Ghanbarian, received the Turcotte Award in 2015 from the American Geophysical Union for his dissertation advancing the science of non-linear geophysics. Muhammad Sahimi is Professor of chemical engineering and materials science, and the NIOC Chair in petroleum engineering at the University of Southern California in Los Angeles. His research interests include flow, transport, reaction, sorption, and deformation in porous media, percolation theory, fracture and failure of heterogeneous materials and rock, and application of artificial intelligence to such problems. He has published over 400 papers and three books, is a Fellow of the American Institute of Chemical Engineers and the American Physical Society, and has received numerous research and teaching awards, including, among others, Humboldt Foundation Research Fellowship Award, the Khwarizmi International Award for Distinguished Achievements in Science, Life-time Achievements Award and Honorary Membership of the International Society for Porous Media, and the Kimberly-Clark Distinguished Lectureship Award.