We, humans, like to think of ourselves as master tool builders- and certainly, as we stand at the threshold of the wonders of the 21st century, we have much to be proud of. But we are really the heritors of a long tradition of life, in all its forms, fashioning tools from lifeless materials born long ago in the hearts of massive stars. So here’s a brief history of technology, from 4 billion years ago to the beginnings of the modern age.