Steve Butler is Associate Professor of Mathematics at Iowa State University. His research interests include spectral graph theory, enumerative combinatorics, mathematics of juggling, and discrete geometry. He is the co-editor of The Mathematics of Paul Erdős (2013). Joshua Cooper is Professor of Mathematics at the University of South Carolina. He currently serves on the editorial board of Involve. His research interests include spectral hypergraph theory, linear and multilinear algebra, probabilistic combinatorics, quasirandomness, combinatorial number theory, and computational complexity. Glenn Hurlbert is Professor and Chair of the Department of Mathematics and Applied Mathematics at Virginia Commonwealth University. His research interests include universal cycles, extremal set theory, combinatorial optimization, combinatorial bijections and mathematical education, and he is recognized as a leader in the field of graph pebbling.