Textbook in PDF format What defines a correct program? What education makes a good programmer? The answers to these questions depend on whether programs are seen as mathematical entities, engineered socio-technical systems or media for assisting human thought. Programmers have developed a wide range of concepts and methodologies to construct programs of increasing complexity. This book shows how those concepts and methodologies emerged and developed from the 1940s to the present. It follows several strands in the history of programming and interprets key historical moments as interactions between five different cultures of programming. Rooted in disciplines such as mathematics, electrical engineering, business management or psychology, the different cultures of programming have exchanged ideas and given rise to novel programming concepts and methodologies. They have also clashed about the nature of programming; those clashes remain at the core of many questions about programming today. Thinking about the different cultures of programming sheds a new light on the technical history of programming, but it also provides a new way of thinking about contemporary programming issues. The answer to what is a good program and how to create one differs dramatically when we see programs as mathematical entities, engineered socio-technical systems or media for assisting human thought. Similarly, the answer to how to best teach programming differs when you see programming as applied mathematics, a new form of literacy or a craft that can only be mastered through practice. To borrow a programming term, cultures of programming are a useful abstraction