Time and Again by Jack Finney
Russell and I listened to this book on a recent car trip. The version we had was abridged to 4.5 hours. I'm not sure how much was cut out, but there weren't any glaring gaps just relationships progressing more quickly than expected and it not being obvious that the problems with Si's time were a result of Vietnam War era disillusionment until the very end of the book (I didn't know anything about the book before we started it).
Time and Again is a very interesting book and I can tell why people have been so captivated by it (the publisher tells us that the novel "has become a truly timeless cult classic with a vast and loyal following"). It combines a sympathetic protagonist, historical detail, and a dash of romance, making the science fiction aspect of the novel approachable even for those who tend to shy away from the genre because of their preconceived notions.
We both liked the novel, particularly Finney's humor and way of articulating things. The concept was interesting, the story was engaging, and the conclusion (both to the plot and the mystery within the novel) was satisfying. However, as I mentioned above, I did feel that a lot was missing when it came to the development of Si's relationship with one of the other characters. I'm assuming that lack of character development is a result of the abridgment.
I believe there is a sequel and I'd definitely be interested in reading it at some point, just to see how things turn out for Si.