This book examines how states adapt to the modern information environment and why some do so more effectively than others. Drawing on theories of military innovation and strategic culture, this book analyzes how the information environment has altered the character of war by blurring traditional boundaries between military operations, political authority, and society. It compares how four major powers—the United States, China, Russia, and the United Kingdom—have understood and integrated information as a form of national power. Using a comparative case study methodology, this book assesses how different political systems, civil–military relationships, and cultural traditions influence whether information capabilities are treated as a supporting tool or as a central instrument of strategy. Well-known and timely cases—such as Russian information warfare, China’s military-civil fusion and Digital Silk Road, and Western democratic constraints on information operations—are used to illustrate broader patterns. This book advances both theory and policy by providing practical recommendations for Western militaries seeking to modernize their cognitive and strategic influence capabilities. This book will be of interest to students of strategic and military studies, defense studies, and international relations, as well as to military practitioners.