A central theme in The Elements of Style is brevity. Strunk and White believe that effective writing conveys ideas succinctly. One of their "principles of composition" is to "omit needless words." Another guideline advises writers to "avoid a succession of loose sentences." Later in the text, they suggest: "Do not explain too much." For instance, they recommend simplifying "in a hasty manner" to "hastily" and changing "he is a man who" to "he." They specifically highlight "the fact that," insisting, "It should be revised out of every sentence in which it occurs."

This emphasis on brevity aligns with Strunk’s character and his teaching style, as White recalls in his introduction to The Elements of Style:

‘‘Omit needless words!’’ exclaims the author on page 23, and Will Strunk truly put his heart and soul into this command. When I attended his class, he left out so many unnecessary words with such force and enthusiasm that he often seemed to leave himself with nothing more to say, like a radio prophet who had outpaced the clock.

White notes that Strunk’s original version of The Elements of Style was "his attempt to trim the sprawling complexity of English rhetoric down to size and inscribe its rules and principles on the head of a pin." Strunk managed to encapsulate everything in just forty-three pages, and White notes that the professor often referred to his work with mischievous pleasure as "the little book."

In addition to encouraging writers to be concise, the authors emphasize the importance of clarity. White, in his chapter on style, argues for clarity in a manner so earnest it's almost startling:

Confusion doesn't just disrupt prose; it also wrecks lives and hopes: a fatal accident on the highway due to a poorly worded road sign, heartbreak between lovers triggered by a misphrased letter, or the distress of a traveler left waiting at a station because of a carelessly written telegram.

After making his point, White acknowledges that unclear writing can also lead to humorous situations. To illustrate this, he cites an instance where the typically serious New York Times informed its readers that Nelson Rockefeller was ‘‘chairman of the Museum of Modern Art, which he entered in a fireman’s raincoat during a recent fire, and founded the Museum of Primitive Art.’’ White then adds his own memorable commentary in his unique style. Regarding the Times quote, he remarks:

This we all enjoy. But consider the tragedies that stem from ambiguity; think of that aspect, and strive for clarity! When you express something, ensure that you have truly conveyed it. The likelihood that you have achieved this is only moderate.

Clarity, along with its related concepts of accuracy and precision, is a recurring theme throughout the book. The authors advise, ‘‘Use definite, specific, concrete language,’’ and ‘‘Keep related words together.’’ An example of a sentence that violates this rule is, ‘‘New York’s first commercial human sperm bank opened Friday with semen samples from eighteen men frozen in a stainless steel tank.’’ The chapter on commonly misused words supports clarity by cautioning writers against using ‘‘disinterested’’ when they mean ‘‘uninterested,’’ or ‘‘enormity’’ when they mean ‘‘enormousness,’’ highlighting that these word pairs are not interchangeable.