This book presents the mathematical tools that politicians use to make rational decisions about health, education, culture, economy, finance, transportation, and national defense for their citizens. The selection of topics addressed is based on the experiences of four veteran politicians who have doctorates or master’s degrees in mathematics. The exposition also considers the mathematical tools used by politicians to capture votes or optimize their impact on the design of electoral districts, i.e., gerrymandering, without forgetting the mathematics applied to parliamentary activity and political science. Aimed at a general educated readership, a basic knowledge of mathematics is the only requisite to understanding most of the book. Certain sections, denoted in the book with a star, contain more advanced material and require some knowledge of undergraduate math. A later chapter is dedicated to applications and techniques of machine learning and the final chapter discusses a variety of cases where political decisions have affected mathematical development. Readers gravitating towards this book are those who are curious about the history of mathematics, including optimizers and mathematicians who would like to learn more about the historical roots of their discipline. There will also be strong appeal to mathematically-oriented economists, political scientists, and people generally interested in mathematics. (Nuno Crato, Professor of Applied Mathematics, University of Lisbon, former minister of Education and Science of Portugal 2011–2015) (Johanna Wanka, Professor of Applied Mathematics, Merseburg University of Applied Sciences, former Minister of Education and Research, Germany 2013–2018)