Even if you never plan to touch F#, I found it a really insightful approach for modeling domain problems - and capturing the rules of the system you are trying

Even if you never plan to touch F#, I found it a really insightful approach for modeling domain problems - and capturing the rules of the system you are trying to model in your code and data types. Really well done, and such a easy read as well. It's not that it's revolutionary, but it one of those things that once you read it both seems obvious and also makes you wonder why we do things any other way.