All historical sources reflect reality in a partial and distorted way. The past, therefore, can be understood only when the limitations of particular sources are recognized and the methods employed in making historical observations, as well as the observations themselves, are constantly tested and refined. Drs. Poos and Smith, in an earlier issue of the Law and History Review, have undertaken such a task when they thoroughly examined my use of manorial court rolls' data for demographic analysis of a medieval English parish.