It is 2197. The Earth has entered the ‘Suryamandalan’ or ‘solar-system’ geological period—the period in which the becoming of the planet has escaped its own boundaries and became fully incorporated into a larger, evolving star system. In response to massive environmental change, scientific and technological developments and extra-terrestrial contact, Earth religions and cultures have gone through an upheaval known as the Second Axial Age, which has involved embracing a radical new metaphysics of matter, time and space. Mars has been settled and terraformed, and a new branch of Buddhism established there: Mangalayana or ‘Mars-vehicle’ Buddhism. This new religion builds on the Dzogchen (“Great Perfection”) tradition of the Nyingma school of Buddhism with its fusion of the individual’s narrative of birth and rebirth with the cosmological story of the emergence and development of the cosmos from an undifferentiated pure ground. It also introduces a new mythos of the relationship between Mars and Earth, personified as bodhisattva and consort, in terms of the mutual gifting of life and animacy across billion-year time scales. Mangalayana Buddhism provides a synthesis of religion, science and practical activity, a new understanding of the relation between personal being and cosmic realities. It spreads amongst the humans, artificial intelligences and human-machine hybrids that work in the extractive industries and terraforming activities of Mars. This text is the introduction to an edition of the Mangalayana text popularly known as the ‘Martian Book of the Dead’, which is used to prepare the dying for the experience of ‘interval-being’ and the possibility of liberation into the deep becoming of their planet, and thus of the cosmos.