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The author has a narrative thread--the conversion of his skin cells into stem cells that begin growing a miniature brain complex. Along the way he explains many of the probabilities, possibilities, and impossibilities of stem cells. The book is surprisingly up to date, right through the Nov. 2018 announcement of gene edited twins in China and even beyond.
Readable and important if you want to know the future for yourself, your kids or Homo sapiens. We are now in charge of evolution and creation.