Simplify the following text for a Grade 10 native English-speaking person.
Original: He is the author of Life Before Life : A Scientific Investigation of Childrenâ s Memories of Previous Lives , which presents an overview of over 40 years of reincarnation research at the Division of Perceptual Studies .
Simplified: Tucker is the author of Life Before Life : A Scientific Investigation of Childrenâ s Memories of Previous Lives .