The subtitle of this book is "The Ten Great Inventions of Evolution" and that's what it's about. But which are the ten things Nick Lane chooses? There's always going to be some room for disagreement about the list, but the ones covered in the book are hard to argue against: the origin of life, DNA, photosynthesis, the complex cell, sex, movement, sight, hot blood, consciousness, death.
By the way, if you liked this book, you might want to try another of Nick Lane's masterpieces: "Power, Sex, Suicide: Mitochondria and the Meaning of Life". I'll try to persuade John Moody to put a review of that book on this site.