This book explores the significance of Turkey's Blue Homeland (Mavi Vatan) naval concept, which defines its maritime rights and interests in the surrounding seas – Aegean Sea, Black Sea, and the Mediterranean. The concept has a powerful socialized definition and a popular appeal across the political spectrum in Turkey with important implications for security in the wider Middle East. The book investigates the impact of geopolitics and domestic-political factors on the concept and uncovers motivations behind its trajectory since 2004 with a particular focus on the last several years, the period when Turkey's naval assertiveness reached its peak following the failed coup attempt in 2016. Based on in-depth interviews with diplomats, naval officers, academics, and researchers in the field, the book takes the reader through a journey on how the Turkish government has reinforced an activist policy since 2016 due to pressures of regional insecurity, domestic coalition logrolling, and nationalist sentiment.