In this overview paper, basic questions related to voluntary internal migration are revisited with a view to adding some of the substantial new field evidence that has emerged in recent years and setting out the policy implications of these findings. The paper addresses internal voluntary migration for paid work. It includes both permanent and temporary migration as well as rural-rural, rural-urban, urban-rural and urban-urban migration. However it does not include forced removal and relocation of people under development and social engineering programmes, trafficking and slavery or displacement by war and civil unrest. It does not discuss nomadic livelihood systems, transhumant graziers or migratory fishing communities although some of the generic arguments will apply to them too.