Bryson closes his book with a cautionary tale: he has argued throughout that human existence is extremely rare, terrifyingly perilous, and extraordinarily lucky. The last thing humans should be doing, then, is undermining our own survival or the survival of other species. Bryson aims to leave his readers with a sense of awe for the planet and its many life forms, so that they will be motivated to take better care of the only home humans have and strive not to destroy ourselves, but to keep life going.