I recently had occasion to quote the line “It is not a book to be lightly thrown aside. It should be thrown with great force,” a variant of which I had always seen attributed to Dorothy Parker.
But it’s my sad duty today to inform you that Parker may not have originated this joke.
A web search led me to a Quote Investigator page from 2013, which does some interesting tracing of various related jokes over time. It tentatively concludes that the line in question came from a book review by Sid Ziff in the Los Angeles Mirror-News, sometime in or before early 1960. Parker did make a couple of amusing comments about throwing or dropping various books (as quoted in that QI page), but there doesn’t seem to be evidence that she originated the not-lightly-but-with-force framing.