Mystery book from my childhood — can you name it? I think of this book often, but over the past week it's been torturing me that I can't remember the name. I'd like to read it again. →[More:]

It's a young adult novel, divided into three sections set across three generations of the same family. The first part takes place in the 1940s or ’50s and involves a romance between two high school kids of very different social status. The girl is poor, and an outcast, and key moments I remember from this section are the other girls being scandalized by the fact that she smokes and also the exchange of love letters between the couple that include the poetry of Edna St. Vincent Millay.

I don’t remember much about the second part, except that perhaps the girl from the first section got pregnant accidentally and the section section is the story of her child. The third section is the story of the grandchild, a teenage boy (in the 1980s?) who’s father barely speaks to him because he is traveling with some musicians or something. The important thing I remember from this part of the book is that his father, over the phone in some far-away place, tells him the story of how Paul McCartney couldn’t think of a name for the song “Yesterday” and so he originally titled it “Scrambled Eggs.”