You're right - I didn't explain what a monad is a priori, just some of their properties and reasons they're useful. Thanks for calling me out on that, as I sho

You're right - I didn't explain what a monad is a priori, just some of their properties and reasons they're useful. Thanks for calling me out on that, as I should have made it more explicit. I didn't mean to "hold the real definition behind my back", just felt that others in this thread had explained the definition better than I could. I also wanted to make the point that the definition is not that important unless you actually want to implement your own monad. You don't need to understand Monads to understand Haskell but they're how you print "Hello world"?? Yes, there's no contradiction here. The idiomatic and easiest way to write Hello World in Haskell involves some unusual, but fairly intuitive, imperative-looking syntax. That syntax only works because the Haskell IO API is monadic, but you really don't need to know that, nor to understand what a monad is, in order to print Hello World. LINQ is very similar to Haskell's do-notation, and LINQ providers (LINQ-to-Objects, LINQ-to-SQL etc) are monadic, but you don't need to know what a monad is to write "from u in users where u.age > 21 select u.name". If you want to write your own LINQ provider, though, it's probably worth knowing the monad laws.