In the rapidly evolving world of software development, one of the key determinants of a product’s success is its usability. Whether it’s a mobile application, enterprise software, or a web-based tool, usability defines how effectively and efficiently users can interact with a software system. Usability is not just about aesthetics or functionality; it is a comprehensive measure that encompasses ease of learning, user satisfaction, and the system’s ability to meet user needs. This chapter delves deep into software usability, its importance, and its broader impact on software success.