Casagrande exhibits total comfort with her topic. Every chapter focuses on a seeming fallacy of grammar and then discloses whether it is, in fact, wrong.

She is not merely throwing around opinions; rather, she consults 14 different texts including dictionaries, The Associated Press Stylebook and Strunk and White’s “The Elements of Style.”

The prospect of reading 101 such chapters might not sound all that appealing, but only because you have not read them yet. Casagrande flashes a delightful, multilayered wit on just about every page, laced with the sort of pleasing wordplay that even a “grammar snob” surely could learn to love.