This presentation explains how to design software using modular abstractions such as “Layer” or “Service”. We will discuss how to apply “top-down” as well as “test-driven” design techniques to implement a modular architecture. You will learn why testability at the module level without having to assemble the whole system is the most important attributes of a module. We will discuss how to plan to throw one away to efficiently design the dynamic behavior of an interface and how to manage dependencies to reduce coupling between modules. At the end of this workshop you will understand why software architects needs a unit of modularity that goes beyond object.