Designing for Usability: Key Principles and What Designers Think

Gould and Lewis's 1985 paper is the founding document of usability engineering — three principles that remain the practical minimum for designing interactive systems: early focus on users and tasks, empirical measurement, and iterative design. The paper is short and surprisingly modern; everything called "user-centred" or "design thinking" since carries its DNA. For product direction, reading the original is clarifying — most contemporary frameworks are elaborations on these three principles, and seeing them stated plainly is a useful reset. A forty-year-old paper that has aged better than most contemporary product literature.