Press On

Harold Thimbleby's Press On explains how to write software for interactive devices so they work reliably and are pleasant to use. Phones, photocopiers and many other everyday machines often fall short of what they could do, and the reasons are not always technical. The author argues that applying established computer science principles leads to better interfaces. Two tools carry the argument: state machines and graph theory, which he uses to analyze existing interfaces and plan new ones. The book also looks at particular designs and inventive fixes to common design problems.

Thimbleby makes the case that programmers, who usually understand the technology better than designers or users, can contribute more to interaction design than is often assumed. Knowing the computing is necessary, but the book also stresses that the right working methods matter for managing the design of systems people rely on. For complex systems, it gives substantial attention to social, psychological and ethical questions that sit beyond the technical layer.

The text highlights its main principles as it goes, and it links related topics across chapters. Each chapter ends with suggestions for further reading. The complete program code from the book, along with additional material, is available on an accompanying interactive website.

The book is intended as a textbook and reference for computer science students and working programmers, and for anyone interested in designing interactive technology.