A user guide, or instruction manual, is a technical document intended to explain the use of products or services, combining written explanations with visuals. From ancient devices like the Antikythera Mechanism to contemporary software, directions have evolved to achieve clarity and accuracy.
Authors like Jonas de Gélieu stressed conciseness, while Lillian Moller Gilbreth focused on uniform phrasing to reduce mistakes. John Wesley connected instructions to moral example, and Plato imagined written guidance for remote learners. These diverse perspectives highlight how directions adjust to audience needs, integrating practicality with teaching.