progress--like those cartoons that begin with an ape and end with a man sitting at a computer--now gets lost in a hundred detours and false starts, intersecting paths and dead ends. It is difficult to find the story line in a tangled bush. Evolutionary theory is not threatened by the disappearance of the main highway. On the contrary, from the beginning Darwin insisted on the randomness of mutations, followed by the editing of natural selection, that lead to the emergence of new species. Still, it is disquieting to look around and see a wilderness of discontinuous and crisscrossing tracks. David Pilbeam once published a book called The Ascent of Man. It is not at all clear that he would do so today. Nonetheless, most of us, including evolutionary biologists, continue to search for and construct stories