Sometimes quotes just don’t want to fit within the structure of our sentences. Unless you are in a legal field, some sciences, or writing for a UK publisher, you can silently tame quoted material in a number of permissible ways. This means that you don’t have to flag your insertions, deletions, and changes by using brackets, ellipses, or footnotes. I’ll break the rules down by major academic style guide.

The Chicago Manual of Style, 15th edition, § 11.8

OK to change silently:

  • case of quotation’s first letter (“paradigms of excellence” to “Paradigms of excellence,” for instance)
  • single quotation marks to double, and vice versa
  • final punctuation that doesn’t fit the grammar of your own sentence, except question marks, exclamation marks, semicolons, colons, and dashes that are not original to the quotation—these must be placed outside the quotation marks
  • endnote and footnote callouts (they can be omitted in quotation)
  • Fraktur and archaic letters (“goodneʃs” to “goodness” and “Vnited” to “United,” for example)

Not OK to change silently:

  • omitted material (use ellipses)
  • inserted material (enclose in brackets)
  • added emphasis, usually expressed in italics (note by inserting “emphasis added” in brackets after the quote)
  • clarifications (“he [James] spoke of troubled times”)

MLA Handbook for Writers of Research Papers, 7th edition, § 3.7

OK to change silently:

  • closing punctuation (quoted material woven into the end of your own declarative sentence can take a period even if not in the original)

Not OK to change silently:

  • basically everything else: capitalization, spelling, interior punctuation, omissions, additions, emphasis, inserted explanations

Publication Manual of the American Psychological Association, 6th edition, § 6.07

OK to change silently:

  • case of quotation’s first letter (“Diamond in the rough” can be changed to “diamond in the rough,” or vice versa)
  • end punctuation (original material ending in a period can be presented as ending in a comma, for instance)
  • single quotation marks to double quotation marks (and double to single)

Not OK to change silently:

  • additions
  • deletions
  • emphasis
  • inserted clarifications

Thus, those in literature (MLA users) are more restricted than those in history, religious studies, and the social sciences (APA and Chicago users). Note that Chicago is a bit more thorough than APA, so APA users may consider following the Chicago rules where APA is vague.

Chicago also embraces what I think is a magnanimous gesture: silently correcting obvious typographical errors. This is preferred to the potentially discourteous use of [sic] to point out the errors of those gone before. (Sic is a Latin term meaning “as such.”) Most of us would rather that others not point out our (or our publisher’s!) errors when quoting us down the line, so be generous when you quote others. Be sure, however, that you are not altering an intentionally unconventional construction or the idiosyncracies of earlier historical moments!

The bottom line is that you always want to be sure that you are reproducing quoted material in good faith—that is, that you are not intentionally or even inadvertently changing the meaning of the original source. But you also want to keep your reader’s eye moving, unobstructed by needless jarring brackets. Always be judicious in your handling of quoted material. Think of those around you: the author of the borrowed material and your reader both.