Time and Again, by Jack Finney
My dad was diagnosed with cancer in 2015 and I remember being so worried that I did not know his absolute favorite book. I have a feeling he was like I am and finds the question “What is your favorite book” to be annoying. I asked anyway. He told me it is “Time and Again” by Jack Finney. I asked why. He said he loves the idea of time travel. We walked over to the book store and I told him I wanted to pick out a bunch of books that he liked. This was one of the 10 books I bought. I suppose even back then it was pretty obvious to my dad how much his books, but mostly his mind and opinions, were important to me.