In 1940, St. Clair McKelway typed a memo to William Shawn, The New Yorker’s managing editor for fact. McKelway was writing a six-part Profile of Walter Winchell for the magazine, and he was unhappy that, in two places in the piece, an editor had changed the word “but” to “however.” He made his case for a page and a half, and concluded, “But is a hell of a good word and we shouldn’t high hat it. . . . In three letters it says a little of however, and also be that as it may, and also here’s something you weren’t expecting and a number of other phrases along that line.” He signed the memo “St. Fowler McKelway.”

The “Fowler” was a joking reference to Henry W. Fowler, who, though not a saint in the magazine’s corridors, was certainly a great authority when it came to matters of grammar and style. A few years earlier, Wolcott Gibbs, another editor, had put together an internal document for new members of the staff titled “Theory and Practice of Editing New Yorker Articles.” It was a numbered list of thirty-one strictures, and in the penultimate one Gibbs wrote, “Fowler’s English Usage is our reference book. But don’t be precious about it.”

The source of what Kenneth Tynan later called the magazine’s “Fowler fixation” was Harold Ross, who’d dreamed up the idea of The New Yorker and brought it into being in 1925. Fowler’s “A Dictionary of Modern English Usage” was published the following year, and Ross seized on it enthusiastically. (The book is usually referred to as “Modern English Usage” or simply as “Fowler,” in the eponymous manner of Hoyle or Roget.) An E. B. White Notes and Comment piece from the late nineteen-forties shows just how strongly the editor continued to feel. Ross—unnamed, merely described as “a tall, parched man”—sees a copy of the book on the writer’s desk, picks it up, and thumbs through favorite passages. “ ‘Greatest collection of essays and opinions ever assembled between covers,’ he shouted, ‘including a truly masterful study of that and which,’ ” White recounted. “ ‘That’s the business that really fascinates me. . . . I got so excited once I had the pages photostatted.’ ” Thomas Kunkel, Ross’s biographer, reported that, from time to time, Ross would read the “that” and “which” entries for relaxation.

Despite the manual’s exalted reputation, the magazine’s style sometimes diverged from its prescriptions. In spelling, Fowler favored “judgement”; The New Yorker has “judgment.” And, whereas The New Yorker’s most famous style choice is probably the diaeresis in a word like “coöperate,” Fowler was against it, preferring the clean “cooperate.” But the magazine fell in line on other matters, including doubling the “l” in “travelled” and “marvellous,” banning the word “transpire” to mean “happen,” and placing a comma after the penultimate item in a series. (Fowler wanted a comma after the final item as well, giving the example “Every man, woman, & child, was killed.” Neither The New Yorker nor, as far as I know, any other publication followed him there.)

And then there was the “that”/“which” business. Fowler actually has more than eight pages on “that” and eleven on “which,” but the part that set Ross’s heart racing concerned the use of the words as relative pronouns—that is, in linking a noun or a noun phrase with a clause that either defines it or merely describes it. Non-defining, or descriptive, clauses unquestionably demand “which” and a comma, as in “He loves his new car, which cost thirty-four thousand dollars.” But, when Fowler was writing, both “that” and “which” were commonly used in defining clauses—e.g., “Congress passed a quarter of the bills that [or which] came before it.” This indeterminacy bothered his tidy sensibilities, and he modestly put forth a proposal: “If writers would agree to regard that as the defining relative pronoun, & which as the non-defining, there would be much gain both in lucidity & in ease. Some there are who follow this principle now; but it would be idle to pretend that it is the practice either of most or of the best writers.” (Fowler had so much to say in “Modern English Usage,” and, indeed, in his letters, that it made sense to save two characters by using an ampersand instead of writing the word “and.”)

Ross and his colleagues later elevated the proposal into policy, and, in part through The New Yorker’s influence, it came to be viewed by most authorities in the United States as a rule. (Although Fowler was an Englishman, the rule has more sway in the U.S. than in Britain.) In the magazine’s archives, held by the New York Public Library, it is touching to come upon a tear sheet of a Phyllis McGinley poem titled “Text for Today,” which was published in the March 31, 1951, issue. In the line “That petrel which refused to perish,” Ross circled the word “which,” and to the page he attached a typed comment: “In prose we would prefer that, so why not in verse?” (As it happens, The New Yorker would evolve a preference for “which” after phrases with demonstratives, such as “That petrel.”)

Near the end of that year, Ross died, at the age of fifty-nine. In his obituary, which marked the first time his name appeared in the magazine, White wrote, “He came equipped with not much knowledge and only two books—Webster’s Dictionary and Fowler’s ‘Modern English Usage.’ These books were his history, his geography, his literature, his art, his music, his everything.”

“Modern English Usage” had a long and rather winding path to publication. “Another scheme that has attractions is that of an idiom dictionary—that is, one that would give only such words as are in sufficiently general use to have acquired numerous senses or constructions & consequently to be liable to misuse,” Fowler wrote, in his neat and confident hand, in a letter to R. W. Chapman, of the Oxford University Press, dated June 20, 1909. “We should assume a cheerful attitude of infallibility, & confine ourselves to present-day usage; for instance, we should give no quarter to masterful in the sense of masterly.”

Fowler’s command of usage was indeed masterly (“masterful,” to him, should mean imperious or strong-willed), but his origins were unprepossessing. He was born in 1858 and grew up southeast of London in Royal Tunbridge Wells, a spa town that his biographer, Jenny McMorris, describes as the “epitome of genteelness.” His father, Robert, was a Cambridge graduate and a schoolmaster who died in 1879, leaving a modest estate, of which Henry, the eldest of eight children, was an executor. At the time of his father’s death, Henry was a student at Balliol College, Oxford; perhaps because of his difficult family circumstances, his academic record wasn’t distinguished.