The urge to collect is a ubiquitous phenomenon which has anthropological, sociobiological and individual psychodynamic roots, but occurs far more frequently among men than women. The author examines the reasons for this gender difference and defines systematic collecting to distinguish it from addictive, obsessive and messy collecting, and from related phenomena such as perversion. The mode of collecting and choice of object are important indicators as to the unconscious psychodynamics of a collector and offer opportunity to describe his structural level. Collecting ranges across a broad spectrum, from an ego-syntonic integrated mode, i.e. sublimation, to a neurotic defence against pre-oedipal or oedipal traumas and conflicts. Alongside this drive-theoretical approach, object and Kleinian theory are also applied to the understanding of collecting. Collecting represents a specific form of object relating and way of handling primary loss trauma, which is different from addiction, compulsion, or perversion. Under certain circumstances collecting can also result in a successful Gestalt or way of life. The paper concludes with a case study showing how collecting develops from a pre-oedipal to a more integrated oedipal mode during the course of the analysis, which is reflected in changes in the transference.