This conclusion presents some closing thoughts on the concepts covered in the preceding chapters of this book. The book bridges the existing gap in migrant research in documenting the link between migration and development. It seeks to provide comprehensive background materials on migration. The book discusses the evolution of different theories and modes of migration and then moves on to a discussion of the different sources and measures for collecting data on internal migration and analyzing trends, causes and consequences of migration. It highlights the issues in using survey data to try to gather information on the number of migrants living away from their family, their occupation and lifestyle at the place of destination. The book emphasizes the importance of characteristics of migrants such as age, sex, marital status, educational level, working status and social and cultural characteristics such as religion, caste/tribe and ethnicity status in knowing the causes and consequences of migration.