The criminal activities provide the main means of support for these tribes and are handed down from one generation to the next. From 1 to 4 million people belong to these tribes, some of which have more than 100,000 members. Some of the subgroups of individual tribes have abandoned criminal activity and have become law abiding. From 60 to 102 main tribes are estimated to exist. Their origins are unknown, although many apparently have existed for centuries. Most are Hindu, with recognized places in the Hindu caste system. Most are of relatively low standing. Crime specializations of the tribes are related to their caste rules and religious traditions. Specialties include house burglary, cattle stealing, daytime theft, pickpocketing, and other activities. The railways have presented new opportunities for crime, particularly baggage stealing. Each tribe has its own traditional methods of carrying out its crime. The tribesmen operate in organized gangs. Most tribes engage in an ostensible means of support in addition to their criminal activities. The three main types of tribes are nomadic tribes, settled tribes that go on extensive criminal expeditions, and settled tribes that engage only in local crime. Although ordinary penal methods have been ineffective in dealing with the tribes, newer methods of restraint and supervision are gradually bringing about their rehabilitation. Eight references are listed.