How did cooperative social groups evolve? This is one of the major questions that concern evolutionary biologists ever since Darwin. One of the first explanations was selection at the level of the group: groups with cooperating individuals increase their reproduction and survival as a whole. Alternative explanations exist, such as selection at the level of the individual: a former beneficiary later rewords a cooperating organism or the seemingly altruist increases its social status thus increases its chances of finding a mate. Another explanation involves selection at the level of the gene: although an individual helping its relatives reduces its direct fitness, measured by its expected number of viable offspring, it enhances the frequency of genes identical to its own in the population. Each one of these models claims centrality or even exclusivity - theoretical primacy - in answering the question of the evolution of altruism. The book is an original and interdisciplinary contribution to the study of the evolution of cooperation. It facilitates a renewed discussion, from a fresh point of view, of classical problems in the fields of evolutionary biology and philosophy of biology; and raises fascinating questions about the history and sociology of science and the complex ties between science and values. From the Introduction by Prof. Yemima Ben Menahem and Prof. Eva Jablonka: Shavit's book discusses the different explanations to the evolution of altruism and how evolutionary researchers commonly decide between them. The author elucidates the nature of the problems and predicaments in this field, tries to identify their sources, and by using these insights offer new ways of thought that will avoid such pit falls in the future. The disposition to undermine observations and experiments of the local population while seeking the cause for universal altruism, and use of a narrow concept of 'group', biases researchers toward a semantic dispute, which completely denies group selection or spots this process everywhere. According to the author the roots of this practice lie, at least partly, in the socio-political echoes of the concept of 'group selection' since World War II. The author explicates an implicit and multifaceted dialog between science and values and argues for a plurality of selection processes in the evolution of altruism. This book is intended for anyone interested in the nature behind the well-known about the human nature. .