The complexities of cortical circuitry are nothing short of fiendish, and the problem of integrating genetic, morphological and physiological details from diverse cortical areas and across diverse species is a worthy challenge to the burgeoning science of neuroinformatics. Though inconsistencies abound, the fact that some trans-areal, trans-specific generalisations are possible, and justified, is a quite remarkable observation. Following the strategy of ‘know thine enemy’, it appears that the cortical fiend has some interesting habits, which we can usefully begin to tag with some shorthand, functional labels.