Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Lynn Margulis is an American biologist and University Professor in the Department of Geosciences at the University of Massachusetts Amherst. She is best known for her theory on the origin of eukaryotic organelles, and her contributions to the endosymbiotic theory, which is now generally accepted for how certain organelles were formed. She is also associated with the Gaia hypothesis, based on an idea developed by the English environmental scientist James Lovelock.