"Blood Music" is a science fiction novella written by Greg Bear. It follows the story of a scientist named Vergil Ulam, who creates self-replicating cells that evolve beyond his control. These cells, initially intended for medical research, begin to develop intelligence and consciousness, leading to unforeseen consequences for humanity. As the cells spread, they transform living organisms and challenge the very nature of life itself. The novella explores themes of evolution, identity, and the potential dangers of scientific experimentation, ultimately raising questions about what it means to be human in a rapidly changing world.