From Scientific American
The authors of this book also see a possibility of extraterrestrial life. "We now know that there are many planets out there in the galaxy, and we have good grounds for supposing that a number of these will have life."
It may be strange life, though, they say, nothing like what we know on Earth. On those principles, Cohen and Stewart (respectively, a reproductive biologist and a professor of mathematics at Warwick University in England) lay a basis for what they call xenoscienceknowledge of the strange. They draw on serious sciencebiology, chemistry, astronomy and physicsand also on science fiction, because the best of it has "made some useful contributions to the scientific understanding of possibilities for alien lifeforms."