Typical forms of criminal activity by professional thieves include pickpocketing, burglary, shoplifting, forgery and counterfeiting, extortion, sneak theft, and confidence swindling. An overview considers professional thieves' historical roots, habitat, means of communication, recruitment and training methods, stock-in-trade, and rules and codes of their culture. It is suggested that 'professional thief' is a label applied by professional thieves to other professional thieves in accord with criteria specified by peer members as the minimum requirements for admission to the fraternal structure. The decline of the professional thief is said to have its roots in the reform movements of the 1890's, combined with the modern plans for urban renewal which brought about serious shrinkage or total elimination of the vice areas that had provided so much interaction and isolation for the professional thief. Seven notes and 41 references are listed.