If it is true that an influx of doubt and uncertainty actually marks periods of healthy growth in a science, then evolutionary biology is flourishing today as it seldom has flourished in the past. For biologists collectively are less agreed upon the details of evolutionary mechanics than they were a scant decade ago. Superficially, it seems as if we know less about evolution than we did in 1959, the centennial year of Darwin's on the Origin of Species.Collection: Past