A basic engineering design theory is created that includes the development of a generalized engineering design procedure. A specific objective is to find the best design that satisfies a given design goal. A more general and powerful objective is to find all of the best designs, and the families of designs, that satisfy an entire field of design problems. A non-dimensional approach is typically used to simplify the procedure and find fundamental design forms. Many examples of the design procedure are provided, often leading to surprising new design results. Emphasis is placed on the understanding and use of this new theory and the resulting generalized design procedure. Together, the design theory and the procedure provide a better understanding of the design process, design goals, design variables, design forms, optimum designs, optimization criteria, direct relationships between design problems and their solutions, design fields and families, scaling laws, optimized scaling and the best ways to graph design results. Examples of the design procedure range from simple to complex; and cover hydrodynamic, aeronautical and mechanical design fields. The many examples include hydrofoils, aircraft wings, and underwater vehicles. Most of these examples are basic and broad enough to be considered classic. Additionally, the theory and procedure can be used in disciplines other than engineering. Furthermore, aspects of the theory and procedure are helpful in research and invention.