This book explains how to apply economic principles to practical problems in business, finance, public policy and other fields. In 17 chapters, it covers topics like mathematical and simulation models in business economics, MATLAB and Simulink design guidelines, importing and reporting data, economic and fiscal models, tax revenue and policy, regional economics, business valuation and applications to finance. Most of the chapters are accompanied by MATLAB code in the appendices. “Think first, calculate later” is the leitmotif of the book. It follows that the text is more a philosophical treatise than a mathematical discourse. Only a few formulas can be found. There are many useful hints, methodological suggestions and a lot of web references in the book. We will mention some of them: methodology of organizing models, conversion of data from various sources (like HTML) to a more useful format, clear explanation of the fiscal system, and many other recommendations that may also be applied to other fields. The book is nicely readable and is recommended for readers interested in philosophical problems of modelling phenomena in business and finance.