Open tubular traps reveal some unique properties that facilitate their applications in analyses of both gaseous and aqueous samples. Low flow resistance, for example, permits their direct coupling with major chromatographic separation techniques. In this paper, the stages of development of the OTTs over a dozen past years are discussed with special attention paid to the technological aspects of their manufacturing and related concepts of their usage. The review covers also the theoretical background and its practical consequences. A separate chapter is devoted to denudation techniques, which have been derived directly from the OTTs, forming a subgroup specific enough to be classified separately.