Bert G. Phillips ( 1868-1936)
Portions of a poem, lines of a song, a pithy quote may capture, with exquisite precision, some point one wishes to explore or affirm in a novel.
Such quotes wrap the work in the familiar cloak of history, of current culture, or of literary tradition and influence, and lend a certain veracity to the story.
However, if one wishes to inject the work of another writer into a narrative one requires permission.
And the pursuit of permissions is often expensive, frustrating, tedious, and time-consuming.
A fact that leaves me wondering why all writers don't just write their own poems, songs, and such -- and avoid the obvious problems all together.
Some writers do.
Robert Jordan (God rest) for one.
In Lord of Chaos (Book Six: The Wheel of Time) Jak o' the Shadows:
"We drink all night and dance all day,
and on the girls we'll spend our pay,
and when we're done, then we'll away,
to dance with Jak o' the Shadows."
-- performs as a perfect equivalent to the traditional soldiers' marching songs - and sustains world building detail as well.
Perhaps SF/F, having no real-time "authority" to lean upon, lends itself to this additional creativity.
But writers who provide their own get extra marks from me.
Groaner Q & A:
No association - for fear of offending someone.
Q: What's the difference between roast beef and pea soup?
A: Anyone can roast beef.