Another distinct possibility: The "51" is not a page number but an artifact identifier.
In large systems, words can mean different things to different departments. A "User" in the billing department is handled differently than a "User" in customer support. DDD creates explicit physical and logical boundaries where a specific model and its Ubiquitous Language apply. 3. Tactical Design: The Building Blocks
To protect the heart of the software, Evans advocates for a strictly partitioned architecture:
One of Evans' most significant contributions is the concept of , which provides a framework for organizing large, multifaceted domains into manageable pieces:
Evans provides a catalog of patterns to structure object-oriented code effectively: martinfowler.com