Alfredo Bautista is a Post-Doctoral Associate at “The Poincaré Institute for Mathematics Education” and a Part-Time Lecturer in the Education Department at Tufts University. He earned his PhD in Psychology from Universidad Autónoma de Madrid (Spain). His doctoral dissertation deals with the analysis of teachers’ and students’ conceptions of teaching, learning, assessment, and evaluation within the field of music performance. He continued his training at University of Victoria (BC, Canada), where he worked as a Post-Doctoral Fellow for a project on mathematical embodiment. His research during that period has looked at how elementary students can potentially enact their geometrical “knowing” while transacting with geometric solids. Alfredo joined Poincaré in January 2010. This opportunity allowed him to merge the areas on which his doctoral and post-doctoral training have focused: the development of better teaching and learning practices, and the field of mathematical knowledge. His current research is looking at how middle school mathematics teachers conceive the notion of “mathematical model,” how they perform when solving modeling activities, and how they use external representations in their teaching, with a particular focus on the Cartesian graph.