If you plan on designing and implementing software using Swift, you need to understand the protocol-oriented programming (POP) paradigm. In this course, take a closer look at POP, and learn how to work with it to more efficiently approach app development. First, review what POP is, exactly, and how it differs from the classical object-oriented programming approach. Next, learn about the pillars of this new paradigm: protocol extensions, protocol inheritance, and protocol composition. Protocol extensions let you define default behavior for conforming types without defining a base class. Protocol inheritance is a powerful feature that lets you create more granular designs. Swift does not allow multiple inheritance for classes—but with protocol composition, Swift types can adopt multiple protocols. Plus, explore generics, and see how to implement a fully functional app using a protocol-oriented approach.