When Santa Fe Institute scientists first started working on economics more than thirty years ago, many of their insights, approaches, and tools were considered beyond heterodox. These once-disparaged approaches included network economics, agents of limited rationality, and institutional evolution-all topics that are now increasingly considered mainstream. SFI continues to expand the boundary of our economic understanding by pioneering fields as diverse as collective intelligence and organizational scaling. This volume, edited by W. Brian Arthur, Eric D. Beinhocker, and Allison Stanger, includes panel and talk transcripts from SFI's 2019 Applied Complexity Network Symposium, with newly written introductions and reflections. Representing both scholarly and practitioner perspectives, this book explores the history and frontiers of complexity economics in a broad-ranging, accessible manner.