Introduction Eric Evans writes in his DDD book: When you care only about the attributes of an element of the model, classify it as a value object. Make it express the meaning of the attributes it conveys and give it related functionality. Treat the value object as immutable. Don't give it any identity and avoid the design complexities necessary to maintain entities. Many objects have no conceptual identity. These objects describe some characteristic of a thing. A value object is an object that describes some characteristics or attribute but carries no concept of identity . ...