Barton Swaim wrote a recent Freelance column for the TLS about the difficulties of blurb-writing. He had been asked by a publisher to write a "two or three-sentence endorsement" for the jacket of a forthcoming book, and he was willing to perform this task, but had a good deal of trouble coming up with anything that sounded both honest and zippy.
"In an effort to get into the mood I tried reading some of the blurbs on the jackets of books on my shelves." And the TLS column that emerged was more about the ridiculousness of the blurbs Swaim found while searching those shelves than about the dull blurb he eventually wrote (and which the publisher ultimately decided not to use).
My own favorite of the examples cited was a 1949 blurb for a novel by John O'Hara called A Rage To Live. Clifton Fadiman (then one of the reigning American critics of contemporary lit) was evidently a man of scrupulous accuracy, cautiously concerned that his recommendation should not contain one word more than the strictest truth. "I know," he wrote, "of no finer presentation in our recent fiction of the culture of the rich Americans of our medium-sized towns."