Within the field of ecology, disturbance can be defined as a physical force, agent, or process, either abiotic or biotic, causing a perturbation or stress, to an ecological component or system, relative to a specified reference state and/or system. Disturbance drive ecosystems, and our understanding of how disturbances interact with biological diversity and scales of space, time, and ecological complexity, have matured over a century of advancement in ecology since early ideas of perturbations and community organization were first formalized. Throughout this book, we approach a set of unifying framing questions for disturbance ecology, including: How can disturbances be categorized in meaningful ways? How do we address scale in disturbance ecology? How does geographic context influence ecological consequences of disturbance, in the near and longer terms? In this introductory chapter, we provide an overview of disturbance ecology and the related topics of diversity and scale that are fundamental to understanding the dynamics of perturbed ecosystems. Subsequently, we outline recent advances in disturbance ecology, which have facilitated greater understanding about dynamic systems and context dependencies. These, in turn, have provided richer insights into the complex manner in which ecosystems change under stress. We survey analytical and methodological advances that are expanding the data flows available to inform disturbance ecology as well as the statistical tools available to investigate disturbance dynamics and ecosystem structure and function. Finally, we lay out four core themes threaded through the remainder of the book: (1) fundamental mechanisms related to ecological theory drive complex system behaviors, including the existence of thresholds; (2) dynamics of ecological disturbance are context-dependent and can be unpredictable; (3) antecedent conditions and the legacies of past disturbances influence contemporary ecosystem dynamics; and (4) natural and anthropogenic disturbances interact in complex ways. Summaries are provided for each of the book’s remaining chapters, highlighting how that material relates to these four core themes. In sum, in this introductory chapter we seek to set a foundation for concepts to ground the remainder of the book. By highlighting constraints in past research and identifying research frontiers, we hope to provide a path forward for advancements in disturbance ecology.