Q. In quoting historical letters or correspondence, what is the current accepted practice as far as leaving mistakes or clarifying mistakes for modern readers? Is it dependent on the work?

A. In scholarly publishing, corrections must be acknowledged, either with the use of interpolations in square brackets or explanations in the notes. Using [ sic] to note that an error occurred in the original is also conventional. Some minor errors or typos may be corrected without acknowledgment. All this requires considerable editorial judgment. Please see CMOS 13.4, 13.7, and 13.59 for more guidance.