The notion of time is omnipresent yet elusive. What exactly is time? Is time what clocks measure, or is time defined to be what clocks measure? Does time as a physical entity exist at all? Or is it purely a mind-dependent phenomenon? Or perhaps neither, as Kant claimed, but an ideal, a priori notion? What is the topology of time? Is it a continuous straight line? Or could it be circular or helical? What about the arrow of time - why is the past different from the future? If time is illusory, how do we explain entropy and the second law of thermodynamics? But why was the entropy ever low to begin with? How does the universe evolve, and what does this say about time? How do we learn to grasp the concept of time, if time isn't a priori form of sensation? Do native speakers of tenseless languages perceive time differently from others? How exactly do we perceive time, and how can we make sense of a timeless physical world? Relatedly, how do complex patterns emerge in nature and in human societies? What are the implications of advancement in computer science for our understanding of evolution, intelligence, and the reality of time?