"Most of us sense something else about time: it is a resource. Moreover, it is a unique resource. It cannot be accumulated like money or stockpiled like raw materials. We are forced to spend it, whether we choose to or not, and at a fixed rate of 60 seconds every minute. It cannot be turned on and off like a machine or replaced like a man. It is irretrievable." - Alec Mackenzie, The Time Trap, 1972.