Thank you Robert Thomas for sharing the link. Lord Buddha's remembrance of thousands of past lives during the first watch of the night he achieved omnipotent enlightenment gave rise to a vast body of Buddhist literature, in many versions, called the Jatakas or Tales of the Buddha's Past Lives. I guess for those who is not a believer, then we have to rely on the field of science/ psychiatry/psychology for answers.
I have watched a documentary that involves Brian Weiss, M.D., an American psychiatrist whose research includes reincarnation and past life regression.
Weiss was not a believer in reincarnation but, after confirming elements of a patient's past-life stories through research into public records, came to be convinced of the survival of an element of the human personality after death. Since 1980, Weiss claims he has regressed more than 4,000 patients. He is a frequent guest on national television and radio talk shows, including: Oprah, Coast to Coast AM, Larry King Live etc and has 7 books on the subject of reincarnation.
There are many critics of past life regression, but it is not something that is made up. Past life regression is mentioned in the old cultures, such as in the Upanishads of ancient India, and Three Lives Book, which Chinese numerologists use the Buddhist/Taoist text the to describe details of past lives.
Also, although Christianity doesn't preach reincarnation, but I've read before some scriptural excerpts that are proof that reincarnation is accepted (although not popularised) - read Scriptural support for reincarnation at
http://reluctant-messenger.com/origen3.html.