This book presents an engaging analysis of the global spiritual changes of the first millennium BCE. Between the sixth and fourth centuries BCE, several new, revolutionary religious and philosophic movements were born throughout the world. Rather than using the well-known label “Axial Age” to refer to this time of religious change, the book argues that a better choice would be the “Age of Awakening”, since it places more emphasis upon the personal, internal dimension of religious experience lying at the core of these developments. Earthshattering spiritual encounters with the sacred led the prophets and sages of the Age of Awakening to redirect people’s attention away from the stagnant traditions of the past towards new forms of dynamic spirituality. The era saw the emergence of a variety of innovative spiritual pathways in both the eastern and western worlds. In classical Greece, Pythagoras and Plato proposed new spiritual and intellectual alternatives to the outdated religious myths and rituals of the polis. The Middle East also played a significant role in the spiritual revolution of the first millennium BCE. As early as the sixth century BCE, the Persian prophet Zoroaster’s revelatory visions about the Truth and the Lie led to the birth of a new religious movement known as Zoroastrianism. At the time of the Babylonian Exile, ancient Judaism underwent a process of radical spiritual renewal largely due to the inspired teachings of the Hebrew prophets. In India, the writers of the Upanishads provided a spiritual reinterpretation of many of the old Vedic myths and rituals. Sages including the Buddha and Mahavira rejected the old sacrificial system of the brahmins and asserted that liberation from the cycle of birth and death could only be found through the practice of asceticism and a general withdrawal from the illusory material world. As such, this book highlights the importance of the de-stabilizing influences of religious experience for understanding the revolutionary spiritual developments of the first millennium BCE.