You recently mentioned that lines from a song cannot be used in a novel, not even two sentences of them. This seems arbitrary to me. It’s like free advertising for them!
My question – because my new novel is devoted to lines from various songs, does it matter how old the song is? What about songs from the 40s, for instance? – MBR
If the song is popular enough to be quoted in a book, they don’t need the publicity. The copyright owner would much rather have the hundreds or thousands of dollars they can and do charge for usage.
For information on works in the public domain, see:
https://copyright.cornell.edu/resources/publicdomain.cfm