My favorite line in Time and Again:
It was an ordinary day, a Friday, twenty minutes till lunchtime, five hours till quitting time and the weekend, ten months till vacation, thirty-seven years till retirement. Then the phone rang.
I'm hard pressed to explain exactly why that cracks me up — maybe how everything seems as though it's going to progress as usual until the guy dies contrasted with the phone call that changes everything?
Anyhow, these books are set in New York City. I've been there a few times, so I had a general sense of the geography. Although this knowledge is certainly not required for reading the books, I think it added to the reading experience.
I also enjoyed the vintage photos that illustrate some of the settings the time-traveling character described. While I was reading the second book, especially, I was pulling up a lot of sections of midtown Manhattan in Google Maps to see at how the streets appear today. (I confessed this nerdy tendency at Pub Quiz last month, and was reassured that at least one other person did a similar thing while reading a book set in London.)