1. The standard table of mortality most generally used in Britain at the present time for life assurance calculations is the A 1924-29 table, which was derived from the experience of assured lives during the period 1924–29. During the quarter of a century that has elapsed since that time there have been substantial changes in mortality rates and the A 1924-29 table is today out of date. The publication of the A 1924-29 Light table, based upon the experience of certain selected offices whose mortality was lighter than average, has no doubt been helpful in providing a table which goes some way in the direction of the lower mortality rates of today. However, this table suffers from the disadvantage that, while the mortality rates at young ages are not low enough for current experience, at some of the older age-groups the rates are too low, with the consequence that the shape of the mortality curve does not accord with present conditions. The greatest proportionate reductions in mortality since 1924–29 have occurred at the younger ages, and there can be little doubt that a new table is needed to provide offices with an efficient and up-to-date instrument for life assurance calculations.