Many living things, including science writers, have nearly identical left and right halves. The evolution of bilateral symmetry paved the way for cephalization—ownership of a head with a brain in it. Popularly, the left hemisphere of the human brain				controls logic and the right, creativity. Scientifically, of course, it's more complicated and interesting than that. In my job of using words and images to clarify scientific and technological concepts, both brain hemispheres get a nice workout. Back