This book investigates the validity of group selection as a mechanism for evolutionary change, arguing against its prevalence in nature. George C. Williams, a prominent evolutionary biologist, utilizes a rigorous logical framework to challenge the then-popular notion that natural selection acts primarily for the benefit of the group or species. He posits that individual-level selection, specifically at the level of the gene, provides a more parsimonious and accurate explanation for observed biological phenomena.

Experts recognize this work as a seminal text that shifted the focus of evolutionary biology toward gene-centered selection. Readers frequently note the dense, technical nature of the prose, which remains a standard reference for students and professionals in the field.