Hi, Happy Easter! I've been using monad transformers for the first time in anger this week. They certainly do the job. However, there's an operation that I keep defining over and over again. It is sort of like lift and return in that it's glue to get operations and values into the monad from outside it. Here are two examples. hoistList :: (Monad m) => [a] -> ListT m a hoistList = foldr (mplus . return) mzero hoistMaybe :: (Monad m) => Maybe a -> MaybeT m a hoistMaybe = maybe mzero return The general idea is that you have some legacy, non-transform operation in some monad MonadFoo, and you are writing an operation in MonadFooT. You want to get the monadFoo value into MonadFooT. So, you say something like: do vInMFT <- hoist vInMF Is this a common enough operation on a monad transformer and it's 'raw' monad to warrant a class of its own? I have 'hoist' methods for several monad transformers, including RamdomMonadT, although I've probably defined them in ways that are overly eager or eat stack/heap, so I'd prefer knowledgable people to write them :) There must be other operations that link the base monad with its transformed version, other than 'hoist' - the runFooT method for example. Perhaps 'hoist' already exists and I'm re-inventing the wheel? Matthew