On the same note, I recently shared a link[0] to his great beginner talk on functional programming languages. This was by far the best introduction to monoid, monads and few other functional programming terms.

Direct youtube[1] for those who don't want to click twice :)

[0]: https://news.ycombinator.com/item?id=25571001

[1]: https://www.youtube.com/watch?v=Nrp_LZ-XGsY

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.

Seconding this! It's one of the very few tech books I've read cover to cover more than once. I similarly find myself revisiting individual pieces of it often.

It completely changed the way I thought about the role of type systems -- and I don't even mean in terms of monads, functors, or any other higher level category theoretic stuff. I mean just the day-to-day business coding idea of representing more of your domain directly in the type system.

I now find that pencil and paper is the best programming tool. It's massively easier to iterate on types and arrows between them than it is to pluck away against and refactor actual implementations.

Would you mind sharing other tech books you've read cover-to-cover more than once?

He is a great teacher. One of the most digestible functional programming sites.

I bought this book when it first came out, and I highly recommend it. It has influenced my implementation of DDD concepts in regular object oriented languages (so not just F# or functional languages).