Once in a rare while you find a book that might have been written specifically for you, addressing your most pressing concerns & questions at the deepest level. Edward Harrison has done exactly that for me in this astonishing examination of the Universe (all that was, is & ever will be) & the many universes humanity has constructed in order to define & grasp that ultimately unknowable Universe. This is philosophy as much as it is cosmology, as Harrison explores the various models of existence that we've created for ourselves over the centuries, quite sure that THIS time we've got it right ... until the next model takes its place. In the end, he argues, there is no direct & immediate understanding of the Universe -- only the models we constantly build as imperfect approximations of it, tailored to suit our current needs & outlooks.This would be heavy going from many writers, but Harrison has the gift of elucidating the most complex material with warmth, wit, humanity, and above all the humility cited by previous reviewers. In so doing, he makes us reconsider all that we take for granted as "reality" & realize just how much of it is a human construct, an agreed-upon fiction that enables us to make some small sense of this endlessly vast Universe & permits us to live within it.Inevitably this leads to both metaphysical & existential questions. Harrison explores these as well, not so much offering answers as encouraging us to think more deeply about those questions ourselves. It's an experience both unsettling & liberating, as we're forced to see ourselves from a perspective far removed from the tight, narrow, often petty focus of everyday life in one transient civilization among many, past & present. How insignificant we are on the cosmic scale, after all! And yet how wondrous that we can not only think of such questions, but wrestle with them.Most highly recommended!