"Gaia and Tityas: What Homo sapiens have done" is a collection of essays covering the stark reality of what has already happened to our planet's ecology, and what lies ahead. The essays provide understanding of what civilization, Tityas, has done to its life support system, Gaia. Readers will gain insight into the challenges society must address as what Gaia makes available declines. Oil, potable water and fertile soil are some of the items that are causing supply problems for human society.