Louis Shapiro is a Professor Emeritus at Howard University. He has taught at Howard for 56 years with research interests in enumerative combinatorics, finite groups, and of course the Riordan group. He is also an avid runner and square dance caller. Renzo Sprugnoli is a mathematician and computer scientist working in the fields of analysis of algorithms and combinatorics. Of particular note his works on the computation of combinatorial sums and the enumeration of lattice paths through Riordan arrays and the special sequences arising in this context. As a full professor, he has taught classes on algorithms, data structures and databases at the University of Florence. Paul Barry is Emeritus professor of mathematics at Waterford Institute of Technology, Ireland.  He carries out research into integer sequences and Riordan arrays. He is the author of the book Riordan Arrays: A Primer. Gi-Sang Cheon is a mathematician working in the field of combinatorial matrix theory. He is a professor at the Department of Mathematics of Sungkyunkwan University in South Korea. Tian-Xiao He is a professor of mathematics and the Earl and Marian A. Beling Professor of Natural Science at Illinois Wesleyan University. His research fields include enumerative combinatorics, Riordan group, numerical analysis, approximate theory, wavelet analysis, and number theory.  Donatella Merlini is a computer scientist working in the fields of analysis of algorithms, enumerative combinatorics, symbolic computation and data mining, subjects she  teaches at the University of Florence. Since her PhD thesis, she has studied both the theoretical aspects of Riordan arrays and the applications in the context of algorithms and data structures analysis. Weiping Wang is an associate professor of School of Science at ZhejiangSci-Tech University, China. His research fields include enumerative combinatorics, combinatorial algorithms, and special functions. His research topics are related to combinatorial sequences, combinatorial summations, and multiple zeta values.