Capitalization in Titles of Works

Q. I am writing a government report, and the first letters of words in the title are supposed to be capitalized. In such a case, should prepositions be capitalized? The government employee who edited my work said that along should be capitalized, but not of, and this doesn’t make any sense to me.

A. Although Chicago style lowercases prepositions (but see CMOS 8.157 for exceptions), some style guides uppercase them. Ask your editor for a style guide.