Q. CMOS 5.195 says that “compare with” is for literal comparisons and “compare to” for poetic or metaphorical comparisons. What is a “literal comparison,” and how does it compare with a “poetic or metaphorical comparison”?
A. A literal comparison examines two things relative to each other in a process that might turn up both similarities and differences (but often with an emphasis on the differences); you’ve demonstrated this usage in your question (“how does it compare with . . . ?”). We might also, for example, compare The Chicago Manual of Style with the AP Stylebook.
In a poetic or metaphorical comparison, the point is to note similarities between things that are not necessarily similar—as in Shakespeare’s “Shall I compare thee to a summer’s day?” People and summer days aren’t literally alike; figuratively, however, it’s a different story (e.g., they might both be “lovely” or “temperate”). This type of comparison—with “to” rather than “with”—is useful for suggesting similarities of any kind: “Please don’t compare me to him. We’re not at all the same.”
For what it’s worth, the “to/with” distinction seems to be fading, as this Google Ngram comparing the frequency of “compared with” with that of “compared to” in books published in English since 1800 suggests (showing “to” overtaking “with” in the mid-1980s—a reversal that happened in the mid-1970s in American English but thirty years later in British English):

Adjusting the terms to “compare to” vs. “compare with” or “compare this to” vs. “compare this with” (and the like) shows a similar trend. If you’re a copyeditor, you might choose to enforce the distinction in formal prose but not necessarily in fictional dialogue and the like.
Q. Is the term “log in to” or “log into” when a user is connecting to a computer?
A. Though the right answer depends on a subtle distinction that’s often overlooked (with, let’s be honest, no significant loss of meaning), formally correct usage would call for “log in to” (with “in to” as two words). The same goes for logging on—or signing in or signing on—to something. In each case, the word “in” (or “on”) forms a part of the verb phrase, where it functions as an adverb rather than as a preposition. For some additional considerations, see CMOS 5.250, under “onto; on to; on.”
Q. Should it be “Nobody but she and Sandra knew if he was lying” or “Nobody but her and Sandra knew if he was lying”? Surely, nobody but the Chicago Q&A will know which is correct—or if neither is!
A. Choose the second version: “Nobody but her and Sandra knew if he was lying.” Rearranging the words in the sentence can help to confirm the right answer: “Nobody knew if he was lying but her and Sandra.” It should now be clear that “nobody” and “he” are the subjects of the verbs “knew” and “was lying,” respectively, whereas “her” and “Sandra” are objects of the preposition “but.” So “her”—which is in the objective case—is correct.
[Editor’s update: It turns out we were a bit hasty with our answer. It’s true that the word “but” can act as a preposition in “nobody but [pronoun]” constructions—as it does in our reordered version of the original, in which the phrase beginning with “but” has been moved to follow the verb “knew.” In that version, the objective “her” is always correct: “Nobody knew if he was lying but [i.e., except] her and Sandra.” But according to Bryan Garner, when the phrase with “but” precedes the verb, “but” can be said to be acting as a conjunction; accordingly, “she” would be the “traditionally” accepted choice in the sentence as originally worded: “Nobody but she and Sandra knew if he was lying.” The version with “her” (as in our original answer), meanwhile, has achieved stage 5 in Garner’s language-change index: “universally accepted (not counting pseudo-snoot eccentrics).” In sum, either answer is acceptable. For the full explanation (and the “dissenting opinion” that supports our original answer with, according to Garner, “impeccable” logic), see Garner’s Modern English Usage, 4th ed. (Oxford University Press, 2016), under “but: D. Preposition or Conjunction.”]
Q. For the labels on a wall at an art exhibit, should it be “courtesy of the artist” or “courtesy the artist”? I am under the impression that “courtesy of” is acknowledgment as well as thanks to the second party for providing something.
A. The phrase “by courtesy of” is typically shortened to “courtesy of.” In credit lines and the like, where space tends to be limited, the phrase has often been further shortened to “courtesy.” In the context of giving credit, all three forms mean the same thing (something like “thanks to” or “kindly provided by”). Pick one and be consistent, though “courtesy of” is probably the best choice in most contexts, room permitting.
Q. Is it “companies and people who dodge taxes” or “companies and people that dodge taxes”? What if the order is changed?
A. The relative pronouns “who” and “that” can both be used to apply to people or groups thereof, so “companies who,” “companies that,” “people who,” and “people that” are all strictly correct. However, readers tend to expect “that” with an abstract collective noun like “companies” and “who” in references to people—collective or not. When the two nouns are paired, choose the relative pronoun that would fit best with the nearest antecedent: “people and companies that,” but “companies and people who.” The choice is somewhat arbitrary, but at least some readers are likely to appreciate the distinction, particularly in that last pairing.
Q. I have run across the phrase “comprised of” multiple times in a book I’m editing. Depending on context, Google Docs wants me to use “composed” or “consisting” or “comprises” or whatever fits. I know M-W says that while the phrase is not technically incorrect, it does sometimes receive scrutiny. Does CMOS have an official standpoint on its use? Thanks!
A. See CMOS 5.250, under “comprise; compose”: “Use with care. To comprise is ‘to consist of, to include’ {the whole comprises the parts}. To compose is ‘to make up, to form the substance of something’ {the parts compose the whole}. The phrase is comprised of, though increasingly common, remains nonstandard. Instead, try is composed of or consists of.” Another option: “is made up of.”
Some of the decisions an editor makes will always be directed at other editors—or at readers who think like editors. “Comprise” is one of those words that, if you misuse it, risks drawing the attention of anyone who pays close attention to dictionaries and usage manuals (not to mention whatever their screens are telling them). So take the hint from Google and revise to avoid “comprised of”—except, for example, in a direct quotation or as an example of dialogue that reflects how many people actually use the term.
Q. Parenthetical material is usually invisible to the grammar of the rest of the sentence, so should it be “a” or “an” in the phrase “a (appropriate) joke”?
A. Although almost anything can be placed inside them (Is it Friday yet?), parentheses don’t make the words they enclose literally invisible. Readers are still obliged to read what’s inside along with the rest of the text. So write “an (appropriate) joke,” which will spare us from reading “a appropriate joke,” a phrase that, stylistically speaking, would be inappropriate.
Q. Would it be “None of us gets to decide these things” or “None of us get to decide these things”? Thank you.
A. “None” can mean “not one” or “not any,” so both are correct. The first sense favors the singular: “Not one of us gets to decide” (“one” is singular). The second favors the plural: “Not any of us get to decide” (“any” is more often plural than singular). Because your example could go either way, consider the context. If the statement applies to people in general, plural “get” would make the most sense. But if it’s a response to one or more individuals, singular “gets” might become the better choice. For some additional considerations, see CMOS 5.250 (under “none”).
Q. My question is about using a definite article before an attributive noun used to identify someone. For instance, “the photographer Ansel Adams took my picture,” as opposed to “photographer Ansel Adams took my picture.” Do you prefer to use the article? Newspaperese style seems to be to omit it, but I’m a holdout. Thanks for any guidance.
A. The version with the definite article is a bit more formal; the version without it is more common in casual prose and journalism, as you suggest. The latter treats the occupation “photographer” as an informal personal title (i.e., like “Doctor,” but without the honorific capitalization) rather than as a descriptive phrase placed in apposition to the name (see CMOS 8.30). Some of our editors, like you, would prefer to retain the “the” in your example (at least in formal prose), but either version is grammatically sound.
Q. Is it correct to use “with” as a conjunction, as in “The regulator received four complaints this month, with two of them related to anticompetitive behavior”? I don’t do it, as I want to avoid it being read as “along with,” but I see this type of construction quite often.
A. According to Garner’s Modern English Usage (4th ed., 2016), the use of “with” as “a quasi-conjunction to introduce a tag-on idea at the end of a sentence” is increasingly common but still best avoided. Your example sentence could be fixed with the help of a semicolon and the addition of “were”: “The regulator received four complaints this month; two of them were related to anticompetitive behavior.”