Are we alone in the universe? The search for extraterrestrial intelligence (SETI) has been given fresh impetus in recent years following developments in space science which go beyond speculation. The evidence that many stars are accompanied by planets, the detection of organic material in the circumstellar disks of which planets are created, and claims regarding microfossils on Martian meteorites have all led to many new empirical searches. Against the background of these dramatic new developments in science, "SETI" critically evalutes claims concerning the status of SETI as a genuine scientific research program and examines the attempts to establish contact with other intelligent life forms in the past thirty years. David Lamb also asseses competing theories on the origin of life on Earth, discoveries of ex-solar planets and proposals for space colonies as well as the technical and ethical issues bound up with them. Most importantly, he considers the benefits and drawbacks of communication with new life forms: how we should communicate and whether we should.