The nature of time is variously understood and varied expressions of time available are critically discussed. The nature of time formation, its structure and textures are presented taking examples from natural sciences and Indian spirituality. The physics and mathematics used to evolve the concept of time are chronologically presented. The mathematical allusion and physical illusion associated with the concept of theories of relativity are analyzed. The mathematical conjectures responsible for evolution of theories of relativity are pronounced. The missing physical reality in theories of relativity in relation to appearance of contraction of length and dilation of time is given comparing these mathematical illusions associated; with the optical illusion of appearance of a scale as bent in water in a beaker to stress the point of illusion - mental and physical respectively. The physical and mathematical nature of time, its measurement and passage and the complex mathematical nature of physical and psychological times are presented.