Although trust is an underdeveloped concept in sociology, promising theoretical formulations are available in the recent work of Luhmann and Barber. This sociological version complements the psychological and attitudinal conceptualizations of experimental and survey researchers. Trust is seen to include both emotional and cognitive dimensions and to function as a deep assumption underwriting social order. Contemporary examples such as lying, family exchange, monetary attitudes, and litigation illustrate the centrality of trust as a sociological reality.