Harmless artificial life forms are on the loose on the Internet. Computer viruses and even robots are now able to evolve like their biological counterparts. Telecommunications companies are sending small packets of software to go forth and multiply to cope with ever-increasing telephone traffic. Protein-based computers are on the agenda, and a team in Japan is building an organic brain as clever as a kitten. Welcome to the startling world of Artificial Life. Artificial Life scientists are taking inanimate materials such as computer software and robots and making them behave just like living organisms. In the process they are discovering much about what drives evolution and just what it means to say that something is alive. Virtual Organisms traces the origins of this field from the days when it was practiced by a few maverick scientists to the present and the current boom in Alife research. Leading technology correspondent Mark Ward presents a fascinating survey of current ideas about the origins of life and the engines of evolution. Through interviews with leading developers of Artificial Life, and through his own compelling research, Ward shows how the convergence of technology with biology has enormous implications. In an accessible, entertaining manner, Virtual Organisms reveals an unexplored avenue in predicting the future of Artificial Life, and whether new forms of Alife may be evolving beyond their designer's control.