This introduction surveys existing literature on South Asian tissue economies and reflects on engagements with diverse modes of biological exchange in the subcontinent. It elaborates the aims and themes of this special issue, which presents essays on caste, gender, and blood donation in Pakistan (Mumtaz and Levay), DNA testing amongst a former Untouchable community in south India (Egorova) and amongst diasporic Indians in Houston, Texas (Reddy), body (cadaveric) donation in India (De Looze), the use of fake blood in Bangladeshi cinema (Hoek), the mobilisation of blood, hearts, and ketones to protest the Indian government's failure to provide redress or care to victims of the 1984 Bhopal industrial disaster (Banerjee), and blood-based political portraits in south India (Copeman). Extending the parameters of classic accounts of the role of substance transactions in the production of South Asian personhood into investigations of contemporary tissue economies, it examines the foundational work of Lawrence Cohen in this area and proposes a set of relations between the double-ness of substance (its promise, as a locus of hope, emerging precisely from its capacity to debase) and its productivity within discourses of civil society and ‘modernisation’.