"The Fertility of the Unfit" by William Allan Chapple addresses the pressing issue of population control, focusing on the declining birth rates in civilized nations and the implications for societal evolution. Chapple builds on the foundational work of Malthus, who identified vice, misery, and moral restraint as checks on population growth. Chapple argues that the modern decline in birth rates is primarily due to the voluntary limitation of family size by those most capable of self-restraint, driven by economic and social considerations. This trend is juxtaposed with the continued high fertility rates among the less fit, including criminals, the impoverished, and those with mental and physical defects, who often lack the same level of self-control and foresight. Chapple suggests that this imbalance poses a significant threat to societal progress, as the proportion of unfit individuals increases relative to the fit. He explores the ethical and practical implications of this demographic shift, advocating for state intervention to prevent the propagation of the unfit while encouraging the fit to reproduce. The book delves into historical perspectives on population control, the role of biological and economic factors, and the potential for surgical interventions to address the issue. Chapple's work calls for a reevaluation of societal values and policies to ensure the future well-being of the human race.