Hi all, I've been reading the gentle introduction to Haskell a bit more closely today and there a few things which I can't quite understand (presumably because they are typo's). I've found two issues with the "Using monads" section [1]. Not sure if this is the right place to report this, but there's probably somewhere here who can fix it :-) The first one is in the state monad data type. It reads: data SM a = SM (S -> (a,S)) -- The monadic type I can't seem to find out what "S" is exactly here. It seems to be a universally quantified type variable, but then it should be lowercase. Considering that it is referred to later on as "s", I suspect this is a type? Further on, a resource monad is described. Here, a lift1 function is given to allow one to lift a normal computation into a resource aware computation, with the following type signature: lift1 :: (a -> b) -> (R a -> R b) A few lines down, the inc operation is defined as follows: inc i = lift1 (i+1) To me, this seems wrong. Even without going into the semantics, it seems that the (i+1) expression does not satisfy the type of the first argument to lift1. I suspect this should have been: inc = lift1 (+1) Gr. Matthijs [1]: http://www.haskell.org/tutorial/monads.html#sect9.3