To every awakened soul the question comes: Why does evil exist? So long as the enigma remains unsolved, Suffering remains a threatening sphinx, opposing God and ready to devour mankind. The key to the secret lies in Evolution, which can be accomplished only by means of the continual return of souls to earth. When once man learns that suffering is the necessary result of divine manifestation; that inequalities of conditions are due to the different stages which beings have reached and the changeable action of their will; that the painful phase lasts only a moment in Eternity, and that we have it in our power to hasten its disappearance; that though slaves of the past, we are masters of the future; that, finally, the same glorious goal awaits all beings, then, despair will be at an end; hatred, envy, and rebellion will have fled away, and peace will reign over a humanity made wise by knowledge. Were this modest work to hasten forward this time by a few years, we should feel sufficiently rewarded. The subject will be divided into four chapters: (1) The Soul and the bodies. (2) Reincarnation and the moral law. (3) Reincarnation and science. (4) Reincarnation and the religious and philosophical concensus of the ages.