Honestly, I don't go looking for these mistakes, I just happen to find them somehow! That I find them so broadly distributed and at the supposedly highest levels is a bad sign of an accelerating cultural decline.
". . . Bell’s principle concern in the chapter is to correct some popular misconceptions . . .."
It is a popular misconception that there is mastery of knowledge apart from mastery of the language with which one expresses it.
Go to the principal's office at once!
(source)
