The Unified Modeling Language User Guide by Grady Booch, James Rumbaugh, and Ivar Jacobson (Addison-Wesley, 1998) tells us that “you can do 80% of your modeling with 20% of the UML” somewhere after page 400.

They would have saved the industry many millions (billions?) of dollars and horrific cases of analysis paralysis if they had said that in the Introduction, but they didn’t.

To compound the felony, they never tell us which 20% of UML is the useful part.