This document provides an overview of three common software development models: Waterfall, Scrum, and Kanban. It defines the essence of each model, including that Waterfall involves long-term planning while Agile focuses on early feedback and minimal planning. Key aspects of each model are outlined, such as phases for Waterfall and roles for Scrum. A comparison table shows differences between the models in terms of task cycle time, feedback lead time, roles involved, and delivery risk. The document recommends Scrum as a personally preferred model.