Manly P. Hall's "Reincarnation: The Cycle of Necessity" offers a compelling exploration of reincarnation, presenting it as potentially the most rational solution to the enduring mysteries of life and the persistent challenge of human imperfection. Drawing deeply from philosophical teachings, this work invites readers to consider the cyclical nature of existence and its implications for spiritual growth.

The book posits that the intertwined laws of reincarnation and karma provide the singular viable explanation for "human unfitness"—the observable inequalities and apparent injustices of life, such as disparities in birth, fortune, intellect, and innate capacities. Reincarnation is described as the continuous rebirths of a singular individuality throughout the grand cycle of life, offering a framework to reconcile the enigmatic problem of Good and Evil.

Key concepts meticulously explored in this foundational source material include:

• Samsara: A Sanskrit term frequently translated as reincarnation, it literally signifies "to incarnate again," "to be re-embodied," or "to return after death to the physical world in another body." It implies the progressive re-embodiments of the ego, self, or sattva.
• Metempsychosis: A Greek term that specifically denotes the passing of the soul at death into another body.
• Transmigration: This term is specifically used to describe the belief in rebirth into lower animal bodies.
• Pre-existence: The concept of the spirit's existence prior to its physical birth.
• Immortality: Referring to the deathlessness or eternal nature of the spirit.
• The Spirit: Considered the divine, permanent, and immortal part of man, capable of independent existence beyond the physical form.
• The "Self" (Sattva): Distinguished from the perishable body and its transient attributes. In Buddhist philosophy, this "self" or sattva undergoes periodic re-embodiment.
• Personality: Refers to the composite and transient nature of mind, emotion, senses, and physical form, which, unlike the spirit, is not reborn.
• The Cycle of Necessity: This is metaphorically described as the "wheel of birth and death." It represents the cycle of consecutive re-embodiment spanning the period from individualized existence to final absorption (Nirvana) or the completion of material existence. The universe itself is understood as progressing and evolving through myriad experiences of existence.
• Karma: The universal law of cause and effect, which provides compensation for actions performed in previous existences. It fundamentally determines the conditions and circumstances of the subsequent rebirth.

The doctrine of reincarnation is not confined to a single tradition; the source material meticulously highlights its presence and exploration across a diverse array of belief systems and philosophies. These include ancient Indian traditions (such as the Vedas, Upanishads, Puranas, and the Bhagavad-Gita), Buddhism, various Greek philosophies (notably Pythagoras and Plato), certain Islamic currents, among American Indigenous spiritual practices, and within discussions among Early Christian Fathers and even in Modern Christendom.

Reincarnation is presented as an ongoing process of profound growth and development—a path through which the invisible divine force continually refines and improves itself. It is characterized as a fundamental law that operates across various kingdoms of nature, including the animal, plant, and mineral worlds, albeit manifesting in different forms. The memory of past lives is said to be preserved within the permanent self and may awaken following initiation into the esoteric Mysteries.

Discover Manly P. Hall's insightful perspective on the cyclical nature of existence and the deeply interconnected laws of reincarnation and karma, which are presented as fundamental to comprehending the human journey towards enlightenment and ultimate perfection.