This book offers a systematic analysis of the nature and origins of money, beginning with a conceptual distinction between money and the real economy before assessing economic stability through the framework of system control. It classifies money into three fundamental categories: commodity money (e.g., gold and silver), currency, and credit/debt. Governments issue currency, while financial institutions generate credit and debt, shaping the complex dynamics of monetary systems.Despite money's ubiquity in daily life — individuals earn it through labor, businesses seek profit, and governments collect it through taxation — it is often perceived as an implicit and unquestioned construct. However, contemporary concerns regarding economic sustainability, resource depletion (such as fossil fuels), and the transformative implications of artificial intelligence, particularly its potential to replace human labor, raise pressing questions: If automation supplants traditional employment, what mechanisms will ensure economic compensation for individuals?By reintegrating money into the analysis of the real economy, this book explores the conditions under which monetary systems influence economic stability. It critically evaluates whether money acts as a stabilizing or destabilizing force, recognizing that while the real economy is bound by physical limitations, modern monetary systems function as social constructs with significantly greater flexibility. This inquiry extends beyond traditional financial and economic discourse, striving to bridge academic scholarship with real-world concerns.Mathematical concepts are presented at an undergraduate level, primarily employing calculus and linear algebra, ensuring analytical depth while maintaining accessibility. Intended for a diverse readership Designed for a diverse readership of academics, professionals, and individuals managing personal or household finances, this book fosters a nuanced understanding of the intricate relationship between money and economic structures.