William Walker Atkinson was a prominent figure in the New Thought movement and a proponent of the doctrine of reincarnation. In his book, “Reincarnation and the Law of Karma,” he explores the concept of the soul’s journey through multiple lifetimes, arguing that past lives influence our present experiences. He connects reincarnation with the law of karma, suggesting that our actions in previous lives shape our current circumstances. 

By “Reincarnation” we mean the repeated incarnation, or embodiment in flesh, of the soul or immaterial part of man’s nature. The term “Metempsychosis” is frequently employed in the same sense, the definition of the latter term being: “The passage of the soul, as an immortal essence, at the death of the body, into another living body.” The term “Transmigration of Souls” is sometimes employed, the term being used in the sense of “passing from one body into another.” But the term “Transmigration” is often used in connection with the belief of certain undeveloped races who held that the soul of men sometimes passed into the bodies of the lower animals, as a punishment for their sins committed during the human life. But this[Pg 8] belief is held in disrepute by the adherents of Reincarnation or Metempsychosis, and has no connection with their philosophy or beliefs, the ideas having sprung from an entirely different source, and having nothing in common.