Luc Anselin is Regents' Professor and holds the Walter Isard Chair in the School of Geographical Sciences and Urban Planning at Arizona State University, where he also directs the GeoDa Center for Geospatial Analysis and Computation. He has written widely on spatial data analysis and geographic information science, including the 1988 classic on Spatial Econometrics. He is the developer of the SpaceStat and GeoDa software packages, and of the spreg-GeoDaSpace module in the PySAL software. Sergio J. Rey is Professor in the School of Geographical Sciences and Urban Planning at Arizona State University, where he is also a member of the Executive Committee of the GeoDa Center for Geospatial Analysis and Computation. His research deals with the development, implementation, and application of advanced methods of spatial and space-time data analysis. He is the creator of the open source package STARS (Space-Time Analysis of Regional Systems) as well as the co-founder and lead developer of the PySAL library.