We can tamper with genetic material to ensure that we have a male child rather than a female. We can create a huge cow with a vast milk yield. We can create mice that are programmed to die of cancer. We already release genetically-reshaped plants into our fields to give us more bread, nicer-looking apples. We can save whole speicies of animals from oblivion by genetic techniques. Tudge describes all this in detail. But do we know what we are doing? Or are we just following our noses as our ancestors did when they developed fire and the axe and destroyed the forests?