It is more than a century now since Charles Darwin published his famous Origin of Species, in which he set forth for the first time a really plausible and convincing case for evolution. The year 1859, when his book appeared, has often been spoken of as marking one of the great milestones of human thinking and yet it is likely that few high school students, even after a course in biology, could state accurately Darwin's basic assumptions or summarize the evolution theory as now accepted. Quite possibly some of them would even deny it for there are many people who still do. I received in the mail not long ago a postcard from the Evolution Protest Movement, bearing a message entitled Evolution-Fantastic Fraud and Billion Dollar Phony. It advertised a work entitled Anti-Evolution Compendium in eight volumes which, it was said, had already been sold to 300 colleges, universities and seminaries-and in all our 50 states plus 15 foreign countries. One of the reasons for this ignorance must surely be that evolution is glossed over, or even entirely omitted, in many high school biology courses. The experimental approach has in recent years yielded such amazing discoveries about the nature of life that life's genesis is often neglected. All too many students, and even their teachers, are prone to think that only the present and future matter; the past can be written off. Yet laboratory exercises illustrating some of the principles of evolution are not hard to plan. Fundamental to the evolution theory are the assumptions of the survival of the fittest (implying the extinction of the less fit species), and of course that there has been time enough for this to happen, and for better fitted groups to come into being. Few students, and perhaps few of their teachers, have any real conception of the vast duration of time, now thought to be at least a billion and a half years, since life first appeared on earth. During this almost infinitely long period environmental conditions have changed so profoundly that older forms of life have become extinct perhaps almost as often as newer ones have originated to take their places. Here is where the biology teacher has his almost unique opportunity. For the evidence of such changes lies all about us. The rocks themselves give evidence of past climates much different from those of today, and their layering tells the story of long gone by epochal events, be they volcanic eruptions or the gradual deposition of sediments at the bottom of ancient lakes and seas with the entombment of myriad living things which are today preserved for us as fossils. These things may easily be presented in a way to stir the student's imagination and lead him to ask many fundamental questions. He will often wish to go out and collect fossils on his own. But he needs first to know something of the major groups of animals, and perhaps plants, to which they belong and how they may be recognized.