Drupal has long outgrown its origins as a humble dorm-room project. The project encompasses a large ecosystem of developers, site builders, and businesses; hundreds of APIs and subsystems; and a wealth of contributed modules and plugins. With the rise of install profiles, distributions, and a UX-driven emphasis on product polish, it's easy to see that complexity growing even more. Making sense of Drupal's codebase and its culture requires breaking down the platform's different layers, and understanding their purpose. As the community grows, that knowledge is also critical for your own growth as a developer. Are you a low-level framework hacker? A product-focused engineer with a UX bent? Or do you focus your time on creating the tools that site builders use to construct the next hot web property? In this session, you'll learn how these layers interact, how to identify problems that stem from "blurry boundaries" between them, and how to be a good coding citizen in the modern world of Drupal. In addition, every session attendee will receive a signed, limited-edition animated GIF of Larry "Crell" Garfield.