The possibility that the supervisory system of Norman & Shallice (1986) can be fractionated into different subprocesses is discussed. It is argued that confronting a novel situation effectively requires a variety of different types of process. It is then argued that evidence of separability of different processes may be obtained by the observation of very low correlations across patients on more than one measure on each of which frontal patients show a performance deficit. Examples of this are provided by examining the Hayling sentence completion and the Brixton spatial anticipation tasks. Finally, differential localization of the subprocesses and hence the conclusion that they are separable is discussed with respect to the localization of monitoring and verification processes in memory.