Despite the vast number of people who use technology as a part of their spiritual and transcendental practice, there is little research on the subject of digital transcendence in studies of Human Computer Interaction (HCI). This monograph reviews the work that HCI has produced in this area but also draws on related research in psychology, philosophy, sociology, anthropology, digital religion, psychopharmacology, and neuroscience. While there are a wide range of perspectives within the literature, transcendent experiences (TXs) are similar across religious and cultural backgrounds but interpretations vary according to world view. Recurring terms describing these experiences are: ineffable, intense, ephemeral, paradoxical, sacred, unity, epiphany, altered perception of time and space, ecstasy, tranquility, gratitude, awe, and reverence. Studies also record benefits of TXs such as substance use recovery and improved mental health. Transcendence and spirituality are deeply subjective experiences and there are many aspects of this topic that academic writing cannot easily approach. For this reason, the authors have combined a traditional academic review with design fiction. They explore the themes in the literature through an illustrated design fiction depicting a near future conference on TX research. This is an extended and illustrated speculation around brain computer interfaces that might evoke TXs. The monograph ends with a manifesto calling for a radically interdisciplinary field that would bridge cultural divides and move beyond models of health and wellbeing to establish new forums and venues for TX research.