 <p>Not only are continuations monads, but they are a sort of universal monad, in the sense that if you have continuations and state, you can simulate any functional monad. This impressive but highly technical result comes from the impressive and highly technical mind of <a href="http://www.diku.dk/hjemmesider/ansatte/andrzej/" rel="nofollow noreferrer">Andrzej Filinski</a>, who wrote in 1994 or thereabouts:</p> <blockquote> <p>We show that any monad whose unit and extension operations are expressible as purely functional terms can be embedded in a call-by-value language with “composable continuations”.</p> </blockquote>