For most laypersons, Darwin's theory of evolution equals survival of the fittest, with one species gaining ascendancy over another in nature's brutal war of attrition. For most biologists, however, evolution is far more complicated. Advanced studies in genetics have given rise to the theory of evolution on a genetic scale, with "selfish genes" battling for supremacy within organisms. Taken to its most extreme, species themselves become almost incidental to the genetic warfare that rages within them. Other biologists take a less narrow view of evolution, believing that many factors--both genetic and environmental--affect how an organism evolves; in Lifelines: Biology Beyond Determinism, author Steven Rose comes firmly down on this side of the argument. Rose, a biochemist, specializes in how memory works, and his book includes some fascinating information about the influence of chemistry in the development of our bodies. So delicate is the balance of DNA chemistry and environment, in fact, that Rose finds the periodic announcements that scientists have "found" a gene responsible for sexual orientation or criminal behavior, for example, to be outrageous and downright dangerous. Simple answers to complicated processes worry him, which may be why he strenuously attacks the genetics-as-destiny stance championed by such well-known scientists as Richard Dawkins.