Great article, but there is one nitpick: you need parentheses in the signature for bind. It should look like (>>=) :: Monad m -- for any monad,

Great article, but there is one nitpick: you need parentheses in the signature for bind. It should look like (>>=) :: Monad m -- for any monad, => m a -- take wrapped value -> (a -> m b) -- and a function which needs it unwrapped -> m b -- unwrap it, and apply that function Or, written the other way: (>>=) :: Monad m -- for any monad, => m a -- take a wrapped value -> ((a -> m b) -> m b) -- and return a function which can take an -- unwrapped value and a wrapped one and -- return another wrapped one Which also makes the comments on the second one a bit inaccurate. It should read "return a function which takes a (function from an unwrapped value to a wrapped one) and returns another wrapped one."