Sweeping survey of literature's many touch points on time and time travel from obvious to obscure. Gleick spends some time in the second half on our definitions of (and how we mostly find ourselves unable to define) time. For e.g., the OED essentially throws in the towel, spending perhaps more words than Gleick enumerating the many senses in which we use 'time', doing away with the faux pas of using the word to define itself: "a point of time as measured in hours...", "a moment or definite portion of time allotted...". As for literature, whether the author takes a straight-forward sequential, chronological narrative approach or chooses to mess with our sense of time, it is essential to how we engage (and are able to engage) with the work. On the other hand, there are fewer (not few) authors who explicitly discuss or problematize time. Among them, and starting with the obvious, Wells, Proust's Rememberance of Things Past, Joyce's Stephen Dedalus ("History is the nightmare from which I'm trying to awake"), Borges (take your pick), T.S. Eliot, Nabokov, Ian McEwan, ... the list goes on. Then there are those from Wells' stock: Heinlein, Asimov, Gibson, and, well... what science fiction author hasn't written about time travel? And those who actually know what they're talking about: John Archbald Wheeler, Richard Feynman, Einstein, Godel, Lee Smolin, Hawking (who hosted a party for time travelers, invitation post-dated--no one showed).
Gleick's establishes early the impossibility of actual time travel but instead uses it as a canvas to explore consciousness and its role in our relationship with time, physical reality, history, and free will. Our sense of time has changed with the advent of the internet--for e.g., we each respond to the same offensive tweet as if the slap were delivered to us at the moment it crossed our 'feed'. But maybe the most surprising is how our vision for the future has changed. The flying cars, space travel, and other fascinations have been traded for nanobots and driverless vehicles in a survey delivered at the turn of the millenium. His conclusion? What time travel comes down to is our desire to elude death. Of everything he discusses in this capacious, breakneck paced review of literature's toe-dipping into time travel, this might have been the most on the nose.