“An old soul is nothing but a very slow learner.” ~Favorite joke of Spirit Guide, James M. Peebles, from To Dance With Angels by Don and Linda Pendleton
Michael Newton, Ph.D is the Founder of The Michael Newton Institute for Life Between Lives Hypnotherapy. He is author of three books on regression therapy: Journey of Souls: Case Studies of Life Between Lives, Destiny of Souls, and Life Between Lives Hypnotherapy.
I believe his work is similar to psychiatrist Dr. Brian Weiss, whose books I've read and recommend.
Here is part one of an interview of Dr. Newton. You can find the rest of the interview at youtube if you’d like to hear more.