This book offers a scientific analysis of why our two main political ideologies evolved. It explains how the competitive, aggressive, sexually selective and monogamous psychology underlying conservatism is a perfect reproductive strategy for use in a K-selected environment of limited resources, while a more competition-averse, pacifistic, sexually promiscuous strategy is ideally adaptive to an environment of free resource availability.It explains how these psychologies arise, how they convey advantage, and even how they have altered history. Without understanding the materials contained within this book, ideologies are merely illogical accumulations of idiosyncratic personal preferences. That they randomly assort into two distinct camps is an unexplainable puzzle. With this book, one can see how ideological psychologies emerged in our species as specific adaptations to environmental conditions we faced, and even how they emerge today in response to those same environmental conditions.