Natural selection and the controversial issues over the units of selection are the subject of these seventeen essays which are grouped in sections that focus on the history of the topic, discuss the levels and units of selection, and present kin, group, and hierarchical models of selection.Undergraduates and graduate students in philosophy and biology will find the anthology particularly useful in its coverage of the roles of mutation, inbreeding, crossbreedings, and selection in evolution, artifact, cause-and genie selection, replicators and vehicles, innate social aptitudes of man, and individual selection and the concept of structured denies.Robert N. Brandon is Assistant Professor in the Philosophy Department, Duke University. Richard M. Burian is Professor of Philosophy and Department Chairman, Virginia Polytechnic Institute and State University. A Bradford Book.