Weaving together a hitherto unattempted history of making and verifying identification documents, In Pursuit of Proof tells stories from the ground about the urban margins of India and Delhi in particular. The book moves with agility across the late colonial era and the postcolonial years marked by ration cards, refugee registration certificates, permits, licences and affidavits. How did the ration card, introduced during the Second World War, crystallize into proof of residence? After the Partition, how did the Indian state classify refugees as poor, displaced and lower caste? Might there be alternative conceptualizations of the much-maligned ‘Licence Raj’? How does proof manifest itself for those living in Delhi’s slums? And how does the unique identification number, termed the Aadhaar, impinge on rural migrants dwelling in the city? Relying on intensive ethnographic and archival methods, the book answers these questions and theorizes the Indian state as one whose welfare capacities of governing are drawn from popular knowledge practices of documenting and proving identities.