Hi Anders, I'm using your monad-peel package to good effect in my project, but I'm having trouble lifting peelIO through a particular monad. What follows is a simplified description of my problem. Say I have this monad: {{{ data M a = M { unM :: forall m. MonadPeelIO m => Reader.ReaderT () m a } instance Monad M where return x = M (return x) M mx >>= fxmy = M $ mx >>= unM . fxmy instance MonadIO M where liftIO io = M (liftIO io) }}} It seems "clear" that there should be a MonadPeelIO instance for M, but I can't for the life of me figure it out. I've tried: {{{ instance MonadPeelIO M where peelIO = M (fmap (\peel (M mx) -> liftM M (peel mx)) peelIO) }}} But this is not polymorphic enough: the peelIO gives me back a function (ReaderT () m a -> IO (ReaderT () m a)) for some *fixed* m, so I can't pack the result of that function into an M again using (liftM M). Have you (or the big brains on Haskell-Cafe, who are CCed) come across this before? Is there an obvious solution I am missing? Cheers, Max