This foundation paper introduces the core ideas behind systems transformation and summarizes the most current thinking about how deep, structural change actually unfolds. It integrates insights from systems science, social innovation, sustainability transitions, and evaluation to clarify the mechanisms, patterns, and conditions that distinguish transformative change from more incremental forms of improvement. Designed as an accessible primer, it helps change-makers build a shared understanding of what “transformation” means—and what it demands—from those seeking to pursue it seriously.