I recall seeing blurbs from this in email taglines and referenced in many other places throughout the years, so I figured I should finally read the whole thing, cover to cover. Although it is clever in places, it is also dated, both in language and in allusions. This may explain why it is only quoted in snippets.
The author says (in the preface) that the original title was "The Cynic's Word Book", but there ended up being such an explosion of "Cynic's" books that "Among them, they brought the word 'cynic' into disfavor so deep that any book bearing it was discredited in advance of publication." (Much like the "Idiot's Guide" books.) However, it reminded me more of a somewhat highbrow version of Jeff Foxworthy's Redneck Dictionary, although with more poetry and less illustrations.
Although calling it "the Devil's" might have sounded overly diabolic or irreverent at the time it was published, it barely raises an eyebrow now. That said, there is much that mocks or denigrates several religions and religious officials. (Then again, it also mocks races of people, politicians, and poets along with priests, so in that sense, it is unbiased in its broadsides.)
I can't say this was a masterpiece, but it does give a time-capsule-like glimpse into the political humor of its time (including multiple references to "the N word" and digs at suffragettes - things considered repulsively offensive today), which is probably more worthwhile than many history books written today. In addition, it does give some witticisms that are still good for today, such as:
“GRAPESHOT, n. An argument which the future is preparing in answer to the demands of American Socialism.”
“AMNESTY, n. The state's magnanimity to those offenders whom it would be too expensive to punish.”
The copy I read came from Project Gutenberg, so it had many typographical errors - but the upside was the price and that I can read it on my smartphone.