Strunk and White are prescriptive, but at the same time the book acknowledges that mastery, and its use for effect, can replace the ideas that they generally prescribe.

> It is an old observation that the best writers sometimes disregard the rules of rhetoric. When they do so, however, the reader will usually find in the sentence some compensating merit, attained at the cost of the violation. Unless he is certain of doing as well, he will probably do best to follow the rules.