More than 7 billion people inhabit the earth and all of them are subject to aging. This book is aimed at persons interested in a molecular explanation of how our cells age. Human Longevity: Omega-3 Fatty Acids, Bioenergetics, Molecular Biology, and Evolution is built on the proposition that we age as our mitochondria age. It suggests a revised version of Harman's famous hypothesis featuring mitochondrial oxidative and energy stresses as the root causes of aging. Human cells are protected from the ravages of aging by a battery of defensive systems including some novel mechanisms against membrane oxidation introduced in this book. This concept is consistent with recent discoveries showing that mitochondria-targeted antioxidants prevent Huntington's disease, Parkinson's disease, and traumatic brain disease in animal models of neurodegeneration. This book explores a unified theory of aging based on bioenergetics. It covers a variety of topics including an introduction to the science of human aging, the Darwinian selection of membranes enabling longevity, a revised mitochondrial membrane hypothesis of aging, and various mechanisms that protect human mitochondrial membranes, thereby enabling longevity.