This textbook introduces readers to essential tools, techniques and methods for intertemporal and strategic modeling in economics. It presents a variety of analytical models covering both dynamic processes and strategic interaction. Students will learn the basic mechanisms associated with the intertemporal approach, on the one hand, and game theory, i.e., the strategic approach, on the other. In addition, a wide range of applications are explored, including growth models, labor markets, international trade, and individual decision-making. Intended for upper undergraduate and graduate students in economics and related fields with a background in mathematics and calculus, this textbook provides a comprehensive introduction to economic modeling and its applications. By avoiding excessive formalism and exploring straightforward examples and applications, it is optimally suited for graduate courses in economics and finance.