Moving away from state categorizations on irregular migration, this Research Handbook critically examines processes and dynamics that generate and reproduce irregularity, and discusses who may count as an irregular migrant. Acknowledging that irregular migration is not just a South-North issue, chapters investigate the many different pathways into irregularity, demonstrating the benefits of understanding dynamics behind irregular migration over statistics. Organised into six thematic parts covering key issues such as approaches and perspectives for research, informal labour and the challenges faced by migrant families, global contributors from a variety of disciplines provide an expert review of geographical and historical paths into irregular migration. Offering their background knowledge and highlighting tools to better understand how irregular migration is linked to geopolitics and migration policies, the Research Handbook on Irregular Migration guides readers through the complex issues facing migrants worldwide. Written in a comprehensive yet accessible style, this Research Handbook will be an excellent resource for undergraduate and graduate students as well researchers and academics interested in migration, policy, law, security, border crossing, informal labour, crime and civil support to migrants.