This book explores the different conceptions of reality in the various interpretations of Quantum Mechanics, demonstrating the intimate connection to philosophy of physics. With interest in the foundations of Quantum Mechanics having revived in recent decades, a number of interpretations have been formulated or rediscovered and these remain in strong competition with one another for acceptance by the scientific community. At the same time they imply quite different notions of reality. The author provides an overview of these conceptions of reality and their embedding in physical theories, interpretations of Quantum Mechanics and related philosophical frameworks. Starting with Aristotle’s principles, the deep fruitful connection between philosophy and physics guides this journey through the foundations of Quantum Mechanics.