In Pursuit of Proof brings forth a hitherto unattempted history of claiming, making, and verifying identification documents in the urban margins of India and Delhi in particular. The book summons to life past and contemporary processes of bureaucratic recognition and administrative verification of subjects by locating them in the everyday material worlds of especially the poor. In attempting to illuminate the paper regimes of welfare that are now being radically transformed owing to the technological infrastructures of Aadhaar, the author resorts to eclectic forms of ethnography and archival research to delineate the pursuit of proof across various timescales. This piece of historical writing moves with methodological agility across moments as disparate as World War II, the Partition, 'Licence Raj', a forgotten but portentous enumeration initiative, and the production of a unique number. What however weaves this vast and ambitious narrative together is the book's intricate and layered exposition of a state whose welfare capacities of governing are drawn from popular practices of knowledge around documenting and proving identities.