According to Cecelia Watson, semicolons aren't just punctuation marks. They're also "a place where our anxieties and our aspirations about language, class, and education are concentrated."

That may seem a heavy burden for one little grammatical tool to shoulder. But in Watson's witty, wily account, it doesn't feel like an overstatement.

"Semicolon: The Past, Present, and Future of a Misunderstood Mark" chronicles the path by which "a mark designed to create clarity" instead became "a mark destined to create confusion." As she examines how this happened, Watson — a self-described "reformed grammar fetishist" — discloses her own evolution from a stickler for strict punctuation rules to someone who embraces the musical flair that a more loose-limbed approach to punctuation can bring to an author's prose.

The semicolon, Watson tells us, was invented in Venice in 1494, soon becoming part of a small tool kit available to writers. For centuries, she adds, punctuation was classed as "part of prosody rather than grammar," and its sentence-structuring functions were viewed as secondary. That changed in the 19th century when dueling grammar manuals began to push for strict codification of its uses.

"How on earth," Watson wonders, "did this idea of the writer as musician, which held on for hundreds of years, transform into our comparatively new expectation that writers must submit to rigid rules?"

One answer is that perfect clarity was desperately sought in some texts. The saga of the Massachusetts Senate's "Semicolon Law," which after much confusion altered hotel-bar hours in Massachusetts in the early 1900s, is especially instructive.

Semicolon: The Past, Present and Future of a Misunderstood Mark, by Cecelia Watson

Still, Watson contends, the semicolon and its brethren have other duties to perform. "Punctuation has to be judged by how it shapes the text in which it's situated," she argues. "You could write perfectly 'correct' English all day and still not have what most of us really want, which is style."

For those who enjoy spending their time in these grammatical weeds as much as I do, Watson raises plenty of diverting style-related questions. Why do semicolons figure so prominently in Raymond Chandler's essays but scarcely at all in his fiction? How did the 4,000-plus semicolons in "Moby-Dick" lend Herman Melville's prose "the freedom of movement it needed to tour such a large and disparate collection of themes"?

"Semicolon" left me hankering for what Watson might have to say about the punctuation circus of Laurence Sterne's "Tristram Shandy" or the energizing use of ellipses in Ford Madox Ford's "Parade's End." In the meantime, there's plenty to savor in this delectable nugget of a book.

Michael Upchurch is the former Seattle Times book critic.

Semicolon
By: Cecelia Watson.
Publisher: Ecco, 213 pages, $19.99.