Joseph Priestly will forever be remembered as the man who discovered and isolated oxygen. It turns out that he was not the first to do so, but the first to recognize the importance of his discovery and to publish his results. He was not the one who named the substance either, but still, he gets the credit. However, his greatest achievement, scientifically, took another two hundred years for anyone to fully appreciate. His discovery that plants refreshed the air and kept an animal alive long beyond when it would have expired in a closed system without plants has led to the science of ecosystems, the study of the inter-relatedness of all living creatures on the earth. Yet, he is largely unrecognized for this. He was a true amateur scientist, a theologian of some repute, and great liberal thinker who had a hand in the formation of the ideas upon which the United States was founded. As a friend and confidant of Benjamin Franklin, and later of Thomas Jefferson and John Adams, Priestly had great influence upon those gentlemen and their radical ideas. This book gives one a brief overview of how that all came about and proved to be a fascinating read, as well. And this from one who does not normally read a lot of history, but the science is what attracted me.