Death Rules explores life from the perspective of death. We are all going to die; our lifespan is limited. That is the way it is. And yet we do our best to avoid death, and at almost any cost. While we accept the fact of death, we seldom talk about it. Now, in the 21st century, science is offering us the opportunity to better understand the vital role of death as it shapes the success and the complexity of life on Earth, and to appreciate our place in the midst of it all. The book explores the natural history of our individual lives and why they must be of a limited duration; how our bodies deteriorate throughout our adult life and why we cannot be rejuvenated; why a finite life might be important for species persistence; why variability is vital for success and why perfection might be a liability; and it considers how we die. Death and the recycling of complex molecules and rare minerals have been vital for the success of life on Earth. Most organisms are not self-sufficient but thrive on the fruits of the labour of others. This has been exploited for the opportunities it offers. As the environment in which a species lives changes, so does the selection of those of its members who are eliminated by death. It is death and failure that shape the direction of evolution, eliminating the less fit by processes driven by the influences of chance and probability. Since life first started it has always had to deal with the reality of death. We have incorporated it into our biology and our culture, and it is everywhere and a part of us. However, if our evolved nature and our beliefs obstruct our ability to adapt to an unpredictable global environment and for which we are not prepared, we face the reality that we too may be subject to the selective power of collapse and death. This book takes a very candid look at death and our place in the complex relationships that shape the evolution of life on a planet with a dynamic and unstable environment.