Outstanding compilation of available information on Tibet and associated states (Sikkim, Bhutan, etc.) gathered from sources limited by the fact that many past visitors and scholars are interested in the religious literature, not sociological documents. Details of productivity, government, history from the 18th Century to 1951, religion, class, etc. are abundant. "Finally the estate includes a sizable number of cattle. Some of them are let out on the 'no birth, no death' contract. Under this, any increase in the flock belongs to the shepherd and any decrease must be made good by him. On the basis of the fixed number of animals the shepherd pays a fixed amount of yak hair, butter, and cheese to be produced each year. Any excess goes to the shepherds."