The aim of this fifth review in the RRN series is to stimulate discussion as to what constitutes 'good practice' in the quantification, identification and registration of beneficiaries in humanitarian assistance operations. The emphasis is on providing practical information concisely and accessibly but the Review does not seek to offer a guide to registration. Indeed, it concludes that total population registration is but one option for establishing numbers and constituent groups within a beneficiary population and discusses registration and alternatives in relation to internally displaced persons (IDPs), as well as refugees and victims of natural-disasters.