Complete clearance of severe psoriasis with photochemotherapy (psoralen–ultraviolet A) was a therapeutic breakthrough in the 1970s. The prominent role of phototherapies for the management of a wide range of dermatological disorders was further promoted by the introduction of narrowband ultraviolet B (NB?UVB) phototherapy in the late 1980s and of ultraviolet A1 phototherapy in the early 1990s. Up to the present, a wealth of data has accumulated from clinical and experimental studies in addition to abundant empirical use on the efficacy, mode of action and, in particular, long?term safety of phototherapies.The value of dermatological treatments is determined by their ability to improve or clear a given disease, by their short? and long?term safety, practicability, accessibility and their cost?effectiveness. Phototherapies have been shown to be highly effective for psoriasis4 and numerous other skin diseases including eczema, parapsoriasis, mycosis fungoides, lichen planus, vitiligo, various pruritic conditions and photodermatoses. Phototherapies are commonly combined with other treatments to provide for an accelerated or enhanced clinical response.