It’s developers’ (mis)understanding, not domain experts’ knowledge, that gets released in production.

—Alberto Brandolini

In the previous chapter, we started exploring business domains. You learned how to identify a company’s business domains, or areas of activity, and analyze its strategy to compete in them; that is, its business subdomains’ boundaries and types.

This chapter continues the topic of business domain analysis but in a different dimension: depth. It focuses on what happens inside a subdomain: its business func‐ tion and logic. You will learn the domain-driven design tool for effective communica‐ tion and knowledge sharing: the ubiquitous language. Here we will use it to learn the intricacies of business domains. Later in the book we will use it to model and imple‐ ment their business logic in software.