Jason Birch (DPhil, Oxon) is a senior research fellow for the ‘Light on Hatha Yoga’ project, hosted at SOAS University of London and the University of Marburg. Jason is also a visiting researcher on the Suśruta Project at the University of Alberta. He is well known for his important paper on the meaning of haṭha in early Haṭhayoga, which has reshaped our understanding of the origins of this term by locating it within Buddhist literature. His dissertation focused on a seminal Rājayoga text called the Amanaska. Through extensive fieldwork in India and the reconstruction of primary sources, Birch has identified the earliest text to teach a system of Haṭhayoga and Rājayoga, namely the twelfth-century Amaraugha. His most recent publication has defined a corpus of Sanskrit and vernacular texts that emerged during Haṭhayoga’s floruit, the period in which it thrived on the eve of colonialism. Jason has published articles in academic journals and critically edited and translated six texts on Haṭhayoga for the Hatha Yoga Project 2015–2020; taught Masters courses and Sanskrit reading classes at SOAS and given seminars on the history of yoga for MA programs at the Università Ca’ Foscari in Venice, Won Kwang University in South Korea and Loyola Marymount University, Los Angeles. He is a founding member of the Centre of Yoga Studies SOAS and the Journal of Yoga Studies, and combines his practical experience of yoga with academic knowledge of its history to teach online courses with Jacqueline Hargreaves on The Luminescent.