Design may refer to both the process of creating a plan, a scheme, or generally an organization of elements, for accomplishing a goal, and the result of that process. Wikipedia states that design is usually considered in the context of applied arts, engineering, architecture, and other creative endeavors, and normally requires considering aesthetic, functional, and many other aspects of an object or a process [319]. In the context of this book in the computing world, design refers to the creation of computer programs, including algorithmic steps and data representations, that satisfy given requirements.

Design can be exciting because it is linked to problem solving, creation, accomplishments, and so on. It may also be frustrating because it is also linked to details, restrictions, retries, and the like. In the computing world, the creation of a computer program to accomplish a computation task clearly requires problem solving; the sense of excitement in it is easy to perceive by anyone who ever did it. At the same time, one needs to mind computation details and obey given restrictions in often repeated trials; the sense of frustration in the process is also hard to miss.

Systematic design refers to step-by-step processes to go from problem descriptions to desired results, in contrast to ad hoc techniques. For program design, it refers to step-wise procedures to go from specifications prescribing what to compute to implementations realizing how to compute. The systematic nature is important for reproducing, automating, and enhancing the creation or development processes. Clarity of the specifications is important for understanding, deploying, and evolving the programs. Efficiency of the implementations is important for their acceptance, usage, and survival.