Grateful acknowledgement is made to CICYT (Comision Intenninisterial de Ciencia y Tecnoiogia), National Plan R+D, Projects N-TXT96-2467 and N­ TXT98-1453 for its financial support. This text presents the economic theories on Utility and Production. In addition, such theories are used to explain the real problems of consumers and firms and several studies carried out by the author are displayed. Some collaboration by other professors of Economics is mentioned in the corresponding footnotes. The responsibility for errors and omissions, however, rests entirely upon tbe author. In chapters 1 and 4 of the book try to present the theory of Utility and Production. Chapter 3 presents new functional forms and two empirical applications, on demand functions and systems. In chapters 2 and 5, the main theorems and properties presented in chapters 1 and 4 are applied. Chapter 6 presents new functional forms and two empirical applications, on production and cost functions respectively.