Robots. Androids. Artificial Intelligence. Scientists predict that the "singularity" -- the moment when mankind designs the first greater-than-human intelligence -- is nearly within our grasp. Believe it or not, truly sentient machines may be a reality within as little as 20 years.Will these "post-human" intelligences be our friends? Our servants? Our rivals? What will we learn from them? What will they learn from us? Will we allow them to lead their...