This book explores the value of Corbett’s seminal work Some Principles of Maritime Strategy over time in a changing context and with evolving technology. It has been over a century since Sir Julian Corbett published Some Principles of Maritime Strategy (1911), yet it is still regarded as a foundational text on maritime strategy. But the character of sea power is constantly evolving, so the continued relevance of this work must be regularly examined. Too often the debate is polarised between a focus on either Corbett’s historical relevance to the early 20th-century Royal Navy or his relevance to strategy today. There is little attempt to bridge the gap and analyse Some Principles over time, changing circumstances, or differing national situations. This book bridges that gap, offering a practitioner’s viewpoint to put the work to a practical test across the past century of conflict, and the evolution of thought and technology. It explores Corbett’s original intent, his core ideas, the errors or omissions in his analysis and method, and where his ideas have been (or still can be) extrapolated, and aims to determine the extent to which Some Principles continues to merit its status as an enduring classic of strategy. The book concludes that despite never being originally intended as a general text, Some Principles nevertheless holds up surprisingly well in terms of both universal application and enduring relevance over time and changed circumstances. This book will be of much interest to students of maritime strategy, naval history, and International Relations, as well as naval practitioners.