The recent literature relating to pathogenesis, clinical features and management of psoriasis has been reviewed. The features of the accelerated epidermopoiesis are described and its relationship to a possible primary fault in keratinisation or dermal influences discussed. The present position on the genetics and epidemiology of psoriasis is summarised. Recent observations on the relationship of histocompatibility system antigens to ordinary and pustular psoriasis could lead to important advances. Clinical discussion is confined to psoriasis in childhood, the hair, nails and mucosal psoriasis; pustular psoriasis and psoriasis arthropathica.