The purpose of Manual IX and Addendum is to provide demographers and population specialists with methods to estimate family planning programme impacts and guidelines for their practical application. Although the publication was compiled two-three decades ago, most methods presented remain relevant. Some methods require limited data and apply simple techniques but they produce crude and not always reliable estimates. Other, more subtle and data-exacting methods yield more robust and nuanced information, but they are more complex and cannot be reduced to an unambiguous application of step-by-step approach.  Most chapters include illustrations utilizing the actual statistics of particular countries. Some subjects developed in Manual IX have been presented in Methods of measuring the impact of family planning programmes on fertility: problems and issues.