This book is the first book on programming as the core subject of a liberal arts education. Its main focus is the design process that leads from problem statements to well-organized solutions; it deemphasizes the study of programming language details, algorithmic minutiae, and specific application domains. Our desire to focus on the design process requires two radical innovations for introductory courses. The first innovation is a set of explicit design guidelines. Existing curricula tend to provide vague and ill-defined suggestions, such as ``design from top to bottom'' or ``make the program structural.'' We have instead developed design guidelines that lead students from a problem statement to a computational solution in step-by-step fashion with well-defined intermediate products. In the process they learn to read, to analyze, to organize, to experiment, to think in a systematic manner. The second innovation is a radically new programming environment. In the past, texts on programming ignored the role of the programming environment in the learning process; they simply assumed that students had access to a professional environment. This book provides a programming environment for beginners. It also grows with the students as they master more and more of the material until it supports a full-fledged language for the whole spectrum of programming tasks: large-scale programming as well as scripting. Our guidelines are formulated as a number of program design recipes.1 A design recipe guides a beginning programmer through the entire problem-solving process. With design recipes, a beginner almost never again stares at a blank piece of paper or a blank computer screen. Instead, the student will check the design recipe and use the question-and-answer guidelines to make some progress.

This introduction to programming places computer science in the core of a liberal arts education. Unlike other introductory books, it focuses on the program design process. This approach fosters a variety of skills — critical reading, analytical thinking, creative synthesis, and attention to detail — that are important for everyone, not just future computer programmers. The book exposes readers to two fundamentally new ideas. First, it presents program design guidelines that show the reader how to analyze a problem statement; how to formulate concise goals; how to make up examples; how to develop an outline of the solution, based on the analysis; how to finish the program; and how to test. Each step produces a well-defined intermediate product. Second, the book comes with a novel programming environment, the first one explicitly designed for beginners. The environment grows with the readers as they master the material in the book until it supports a full-fledged language for the whole spectrum of programming tasks. All the book's support materials are available for free on the Web. The Web site includes the environment, teacher guides, exercises for all levels, solutions, and additional projects.