What is Time? Assuming no prior specialized knowledge by the reader, the book raises specific, hitherto overlooked questions about how time works, such as how and why anyone can be made to be, at the very same instant, simultaneous with events that are actually days apart. It examines abiding issues in the physics of time or at its periphery which still elude a full explanation such as delayed choice experiments, the brain's perception of time during saccadic masking, and more and suggests that these phenomena can only exist because they ultimately obey applicable mathematics, thereby agreeing with a modern view that the universe and everything within it, including the mind, are ultimately mathematical structures. It delves into how a number of conundrums, such as the weak Anthropic Principle, could be resolved, and how such resolutions could be tested experimentally. All its various threads converge towards a same new vision of the ultimate essence of time, seen as a side effect from a deeper reality.

Is there such a thing as a fundamental reality, something which was around before our universe came into existence and which will still remain when all matter, time, and space itself ultimately disappear? Something fundamental which, in turn, can make space and time and matter arise from seemingly nothing? Under most cosmological and physical models, the last known remnants of reality are the disembodied laws of mathematics -- beyond which it is extremely difficult to probe further. Using contemporary physics, narrated at popular science level, Chris Ransford shows why full nothingness -- a nothingness within which even the disembodied laws of mathematics would not exist -- cannot possibly exist, and what most likely underpins and enables reality. This leads the author to a few thoughts as to how such knowledge may be verified, and then deployed to achieve a better alignment with reality.