Was Darwin the most revolutionary scientist ever? If, by revolutionary, we mean the scientist whose discovery initiated the most seismic overturning of pre-existing science, the honour would at least be contested by Newton, Einstein and the architects of quantum theory. Those same physicists might have outclassed Darwin in sheer intellectual fire power. But Darwin probably did revolutionize the world view of people outside science more comprehensively than any other scientist. I want to recognize four bridges to evolutionary understanding. The first bridge is to natural selection as a force for weeding out the unfit. The second bridge is the recognition that natural selection can drive evolutionary change. Bridge number three leads to the imaginative grasp of the importance of natural selection in explaining all of life, in all its speciose richness. Bridge number four is the bridge to public understanding and appreciation. Darwin crossed it alone, in 1859, by writing On the Origin of Species. The fifth bridge, which Darwin himself never crossed was neo-Darwinism or what I shall rename digital Darwinism because the essence of Mendelian genetics is that it is digital. As crests get longer, or eyes rounder, or tails gaudier, what is really being carved by natural selection is the gene pool. As mutation and sexual recombination enrich the gene pool, the chisels of natural selection carve it into shape, working away through geological time. It is an image that might have seemed strange to Darwin. But I think he would have come to love it.