I have enjoyed writing this book. Some of my ideas are controversial. Some of them I know to be true though I have not sufficient evidence for a conviction. My intention is that you should realise that microbes will be as important in the future of the earth as they have been in the past. They have led to our existence, and may help to prevent our destruction; they may even save us from ourselves. i As a student, I was taught that a scientist must be objective, and that every statement or observation must be documented. Also, that a scien­ tist must seek the truth, and not be satisfied with less. It took me a long time to realize that no human being can be completely objective, and that the truth, even scientific truth, is a chimera. The most that we can get with our human minds and feeble experimentation is an approximation, and all we can hope to contribute is a better approximation than we have had to date. Newton's theories were regarded as absolute until Einstein came along; and now it seems that Einstein may be inadequate.