"Lynn Margulis is one of the most successful synthetic thinkers in modern biology. This collection of her work, enhanced by essays co-authored with Dorion Sagan, is a welcome introduction to the full breadth of her many contributions." EDWARD O. WILSON, AUTHOR OF THE DIVERSITY OF LIFE "An important contribution to the history of the 20th century. Read it and you will taste the flavor of real science." JAMES LOVELOCK, AUTHOR OF GAIA: A NEW LOOK AT LIFE ON EARTH "Truly inspirational and of fundamental importance. This thoughtful series of essays on some of the largest questions concerning the nature of life on earth deserves careful study."PETER RAVEN, MISSOURI BOTANICAL GARDEN