Domain-Specific Languages (DSLs) are programming languages that are tailored to a particular application domain. This essential focus of DSLs allows to more concise and understandable programs, with a tight stakeholder integration, and when done properly, to improved code quality. The course will feature the current state-of-the-art on both the design and implementation of DSLs. The course will emphasize the different design dimensions of DSLs, the involved language paradigms and features, and the drawbacks with respect to simple API modeling. As a student, you will also learn the difference between internal and external DSLs. In parallel, you will learn how to effectively implement a DSL from scratch, using modern language workbenches and programming languages that enable the construction of expressive and effective DSLs.