Social-emotional learning (SEL) refers to a set of competencies that form the basis of human interaction. So, SEL in schools is no fad. But what would happen if every school actively wanted to bring in SEL tomorrow? Using the articles in the special issue on SEL as a springboard, this article looks at the neurological basis of SEL, SEL best practices, approaches to SEL instruction, assessment, and the complex issue of SEL and equity, and it reflects on the implications of these areas for scaling up sooner rather than later. Specific guidelines are provided, starting with this basic point: There are not enough experts available to guide this process, so schools must invest in staff learning about SEL, its rootedness in our biology, its basic role in accomplishing everything humans try to accomplish, and what we know about best practices and must provide cohort-based, ongoing professional development experiences that provide continuous support.