Clean air is a basic requirement for good healthy. NASA was faced with the task of creating a life support system for extended living in space and began extensive studies on treating and recycling air. After 25 years of research, NASA figured out the best way to combat indoor air pollution is with plants. It makes sense. There are beautiful color pictures of various species, and plants are rated according to their effectiveness in the removal of specific airborne toxins. All plants are not created equal. The author’s ratings on ease of cultivation, susceptibility to insect infestation, and transpiration (humidification) rate allow the reader to select the “right” plants. I highly recommended this book that is easy to read and understand.