James Hiebert is the Robert J. Barkley Professor of Education at the University of Delaware, and a Fellow of the American Educational Research Association. He co-authored the books The Teaching Gap, and Making Sense: Teaching and Learning Mathematics with Understanding, and edited the books Conceptual and Procedural Knowledge: The Case of Mathematics, and Teachers, Teaching, and Reform: Perspectives on Efforts to Improve Educational Outcomes. He has served as PI or co-PI on 13 grants funded by the National Science Foundation or the U.S. Department of Education.  Jinfa Cai is the Kathleen and David Hollowell Professor of Mathematics Education at the University of Delaware, and a Fellow of the American Educational Research Association. He served as the Editor-in-Chief for the Journal for Research in Mathematics Education (2017-2020).  He is interested in how students learn mathematics and pose/solve problems as well as how teachers can provide and create learning environments so that students can make sense of mathematics.  He has served as Program Director at the National Science Foundation.  He was the Editor of the 2017 Compendium for Research in Mathematics Education (published by NCTM).   Stephen Hwang is a researcher at the University of Delaware and is the Project Coordinator for the NSF-funded project, Supporting Teachers to Teach Mathematics Through Problem Posing. He served as the Assistant Editor for the Journal for Research in Mathematics Education (2017-2020). He is interested in mathematical problem posing and how teachers can learn to use problem posing to provide robust learning opportunities for their students. He is also interested in the processes of mathematical proof and justification and the development of mathematical habits of mind.  Anne Morris is a professor at the University of Delaware. She served as an Associate Editor for the Journal for Research in Mathematics Education (2017-2020). She is interested in how educators can store knowledge about teaching in instructional materials that are readily useable by teachers so that improvements accumulate over time. She is also interested in children's and preservice teachers' understanding of deductive argument and how to develop it through classroom instruction.  Charles Hohensee is an Associate Professor at the University of Delaware. He served as an Associate Editor for the Journal for Research in Mathematics Education (2017-2020). He is interested in backward transfer, which is how students’ ways of reasoning about a previously-encountered mathematics concept changes when they engage in learning experiences about a new mathematics concept.