A Tree Grows in Brooklyn
I just finished A Tree Grows in Brooklyn (1943) by Betty Smith. Outstanding!

I had never read this before, but I had heard of it. I was pleased to find it really deserves its reputation. It's a joy to read. I'm from Massachusetts, so it was a little embarrassing to have the snobby doctor be from Boston, but I won't claim there aren't people like that there.
It was made into a movie in 1945; I think I will put that on my "to be watched" list.
Update: I watched the movie online (none of the streaming services I subscribe to had it). The librarian isn't awful in the movie! She's one of the worst people in the book, but she's kind of nice in the movie.
James Dunn won an Academy Award for playing Johnny Nolan. He did do a good job, but I thought he looked a bit too old. He was in his forties at the time. Perhaps the most prominent feature of the Nolans is how poor they are, but I also think it's important how young they all are. Sure, Francie and Neeley are just children, but Katie and Johnny aren't really much older. Johnny Nolan is so tragic in large part because he's so young.
Update: It was also a movie on television in 1974. I watched that online as well. Cliff Robertson played Johnny Nolan. He was in his fifties at the time!