This textbook offers a compact, yet formal, synthesis of the broad field of consumption theory. Written in a coherent and accessible way, this book introduces graduate and postgraduate students to dynamic optimization applied to consumption under certainty and uncertainty, in discrete and continuous time. Delving into deterministic and stochastic models, including the use of Brownian motions, the book offers a deeper understanding of consumption decisions and their impact on asset pricing and investment in partial and general equilibrium. This book compiles lecture notes from advanced courses in micro- and macroeconomics, ensuring a self-contained introduction to the subject. Balancing simplicity with analytical rigor, the book equips readers with essential methodological tools for advanced research in economics. With empirical evidence and exercises integrated throughout, this textbook stands as the go-to resource for scholars and students alike, fostering further theoretical explorations in the field. Basic knowledge of economics, mathematics, and econometrics is recommended for a comprehensive understanding.