A: Reincarnation has never been a doctrine of mainline Judaism and does not seem to be typical of most modern Jewish thought, although the idea has cropped up from time to time among certain Jewish sects. The Zohar (book of Jewish mysticism)  is said to refer to it several times, both in the sense of the soul of a person entering another person, and even into the body of an animal or insect as a sort of purgatory. The Karaites were apparently the first Jewish sect to adopt the notion of reincarnation in the eighth century, apparently at least in part in an attempt to account for the suffering of innocent children.  The argument was that they must have sinned previous life in order to deserve such hardship. (See John 9 for Yeshua's explanation) Saadia Gaon called the idea of reincarnation "nonsense and stupidity." The Jewish philosopher Jewish Albo also rejected the idea of the "transmigration of souls" in the fifteenth century..

• "What Does Judaism Say About . . .?" by Louis Jacobs
• The Encyclopedia Judaica, article "Afterlife"