What, Then, Is Time?

I have physically but not mentally completed this book. Though it is quite interesting I may not attempt to read it again. However, this text reminds us that time is a mystery and regardless of how in-depth we try to get in exploring it's varied phases (past, present, future) it is still a mystery, existing in the "imaginative structure of memory and expectation". It can be localised, viewed as motion, thought of as an image of eternity, considered as a number, etcetera, etcetera, all in all, time is a mystery, and that is the beginning and end of it...
(Many philosophers are referred to in this text such as Plato, Kant, Hegel, Newton, Einstein, Leibniz, etc, in time I will read them...)