The goal of the next four chapters is to get you writing Shiny apps as quickly as possible. In Chapter 1, I’ll start small, but complete, showing you all the major pieces of an app and how they fit together. Then in Chapters 2 and 3 you’ll start to get into the details of the two major parts of a Shiny app: the frontend (what the user sees in the browser) and the backend (the code that makes it all work). We’ll finish up in Chapter 4 with a case study to help cement the concepts you’ve learned so far.