In "A tale of two cases: Lessons for education from the study of two boys living with half their brains" (M. H. Immordino-Yang, 2007), I showed that Nico (missing his right cerebral hemisphere) and Brooke (missing his left) had compensated for basic neuropsychological skills to previously unexpected degrees and argued that the ways they had compensated revealed general principles about the active role of the learner and the organizing role of emotion and social interaction in development. Here, I briefly review my findings and interpretations of that work as background for readers to engage in the cross-disciplinary conversation that follows in this journal issue.