We have only one planet, but we're using the resources of five or more planets. Climate change is very real. Freak storms are increasingly common. While there are water shortages in some regions, there are floods in others. In response, corporations are adopting sustainability practices, and products are marketed as "green," "eco-friendly," "environmentally friendly," and "energy efficient." What does it really mean to be sustainable? How can people determine which products are truly better and greener?