Journalist Andrew Solomon spent a decade interviewing families where children differ dramatically from their parents - deaf children of hearing parents, children conceived in rape, prodigies, children with Down syndrome, autism, schizophrenia, or multiple disabilities, and children who become criminals. His research explores what he calls 'horizontal identity' - characteristics that children do not share with their parents and must learn from peers or the broader community. Solomon examines how parents find meaning in raising children whose lives they cannot fully understand and how children navigate identities their families did not choose and often initially reject. The book combines extensive interviews with research on each condition, providing both intimate portraits and contextual information. Solomon, who is himself gay and dyslexic, writes with personal investment in questions about difference and belonging. The book challenges assumptions about what constitutes disability, illness, or identity, showing how categories that seem medical or genetic are also culturally constructed. At nearly a thousand pages, the book is comprehensive, covering each identity with depth that briefer treatments could not achieve. For readers interested in disability, parenting, identity, or the complexity of human difference, Solomon provides monumental work that resists easy conclusions.