The genre of the recommendation letter, a friend once observed, is hyperbole. Everything has to be stated in the superlative, so one reads for degrees of overstatement, hyper- and hypo-hyperbole, becoming a progressively more sensitive seismograph, searching out quavers and tremors or microscopic proportion.
The blurb is a clear cousin or sibling, at least in the most common form in which sparrows of adjectives crossbreed with surprising frequency, occasionally to be found perching with monikers and epithets (the good kind).
The paperback edition of Tayari Jones’s Silver Sparrow lavishes its (richly deserved) lavishings in one-liners:
Even in a more substantial blurb, like this one (with which I heartily agree), written by Melissa Pritchard for Ciatlin Horrocks’s This Is Not Your City (Sarabande 2011), the lavishing raises its volume: