This work examines what is perhaps science's ultimate question: the origins of life on earth. Paul Davies presents a series of recent discoveries which are leading to some startling theories about the origins of life on earth. New life forms have been discovered in bizarre habitats: deep underground and under the ocean floor. The conditions thought to be necessary for life have thus been radically revised and this has led to the realization that life could very well exist on other planets hither to thought to be inhospitable. Further, cosmic impacts can transport these rock-dwelling micro-organisms from planet to planet across the solar system and beyond. so life could quite easily travel from earth to other planets. Indeed, life could have arrived on earth from elsewhere.