The author of "Rescuing the Planet: Protecting Half the Land to Heal the Earth" provides an introduction to the Half Earth idea: that "up to half of the earth’s land and water must remain permanently available as living space for other species." The goal, he continues, "is not to exclude people or banish people’s activities, but create a series of shared spaces where people will tread lightly." Doing so will "keep 90% of life and awareness alive."