The book does make sense in that a child's secure or unsecure attachment can have an impact on the child's life in the future. However, just because the child had a secure attachment, concluding that the outcome at the very end will be good is not provable. The events in the future that can have dramatic effects on someone's well-being in completely unpredictable. This idea of attachment and whether the outcome in the future is good or bad could be plausible in ideal conditions. Otherwise, I do not think anyone can jump to conclusions from just looking at someone's childhood attachments.
