When Charles Darwin was composing On the Origin of Species, he had to face an extremely frustrating problem. The fossil record, despite initially inspiring some of his evolutionary notions, was largely a mystery. Part of the problem stemmed from the gaps and missing chapters in life’s history. But there was also a more hopeful aspect of the argument that Darwin hasted to point out as he wrote new editions of his most famous book. Despite the fossil record’s unavoidable incompleteness, paleontologists of Darwin’s day had only just begun to discover the vestiges of prehistoric life that the world’s rocks contained. There was far more to find than had been turned up. And that’s still true.