This seminal book brings together many of the ideas that have shaped how we think about strategy today. Across fifteen chapters, leading scholars introduce major theories from classics like the resource-based view and game theory to newer perspectives on platforms, cognition, and value capture, explaining not only what these theories say, but why they matter. Each chapter traces how a theory developed, how it helps us understand real strategic decisions, and where unanswered questions still remain. Rather than promoting one "right" way to think about strategy, the book highlights how different theories illuminate different parts of a complex world. It is written for researchers, students, and practitioners who want to navigate the field's diverse approaches and deepen their judgment about when and how to apply them. Ultimately, this volume invites readers into an ongoing conversation about how strategy works and how our theories can continue to evolve. This Guide will be ideal for researchers and doctoral students who want to navigate the field's diverse approaches and deepen their judgment about when and how to apply them. It will be particularly useful for doctoral seminars.