This book offers a clear account of timelessness together with the discussion of temporality in fundamental physics and cosmology. The multi-disciplinary approach to the problem of time and timelessness shows the remarkable difference between pre-relativistic debates and current developments. This book thoroughly discusses notions of timelessness and time emerging in the most recent literature on Quantum Gravity, String Theory and Cosmology. The contributions explore, among many aspects, the historical-philosophical roots of the notions of temporality and atemporality, the role of mathematics in defining time and temporality with respect to both order relations and causality, approaches to quantum gravity and cosmology that make use of quantum fluids and condensate to approximate space–time in general relativity, time and timelessness in black holes and the problem of cosmological time in bouncing cosmologies. The novelty of this volume lies in the interaction among scientists, philosophers, and historians in exploring the nature of time and timelessness and the origin of these concepts. The book represents a valuable toolkit for researchers and graduate students in physics, cosmology, philosophy and the history of those fields.