In this book Ian Stevenson presents an empirical case for reincarnation. If that combination seems odd to you now it won't by the end of the book. He carefully and prudently refrains from arguing that reincarnation occurs; instead, he records some unusual and seemingly anomalous facts--carefully documented--and gives the reader the option of deciding whether reincarnation is or is not the best explanation for them. Stevenson remains open to the possibility of alternative explanations for how young, scarcely-verbal children can recite details about the lives of people they have never met, but by the end of the book it's clear that the usual mechanistic and biological explanations cannot suffice.
Simply put, Stevenson interviews kids between the ages of (usually) 2 and 7 who have stories to tell about who they were, by their own description, in a previous life. He then attempts to identify the previous personality, and to verify or disprove every detail of the child's story. He writes about kids who talk about being a fishmonger with a green jeep in a distant town they have never visited, and don't know anyone who has visited; kids who have birthmarks corresponding to entry and exit bullet-wounds they claim to have received when murdered, and who give the details of their deaths, later verified; and kids who claim to have another family and reveal that other family's secrets. Such cases are the tip of Stevenson's iceberg.
Stevenson makes a few speculative claims in his concluding chapters, and I think he could be more appreciative of the historical criticisms of vitalistic thinkers, from the alchemists to Goethe. He speculates a bit too much about the implications his research has for theories of personality, and in a few places his self-restraint feels strained. But his claims for a mind-brain dualism are excellent, as are his suggestions about the self-reconstructing capacities of the human psyche. This last is particularly important as some writers in this area, often under the spell of Jung, have denied the individual's capacity for self-reflective growth. If you seem backed into a corner after reading this book, remember that even if Stevenson's hypothesis is correct, the theory of reincarnation provides no definitive insights to the nature of the psyche, and offers no absolutes regarding conduct, morality, and change.