What is theory? What do theorists do? Doctoral students and academics often engage with theory, but there is sometimes misunderstanding about what theory is, does, and explains. This book explores these questions, giving students and academics alike in public administration and management an idea of the breadth of depth of theory use, development, and application.The journal, Administrative Theory & Praxis (ATP), has for more than four decades explored these questions and more within its pages. The aim of the volume is to demystify the word ‘theory’ and the chapters in this edited volume showcase the various ways in which ATP authors have explored their own ways of using and describing administrative theory. Through this volume, readers will have a broad understanding of how theory shapes thinking and application in public administration and management.The chapters in this book were originally published in Administrative Theory & Praxis.