There is a part of CMOS 7.75 that continues to trouble readers, probably because it is an exception to the general rule (stated at 6.9) that “periods and commas precede closing quotation marks, whether double or single.”
A look back to 1906, when the more straitlaced 1st edition of the Manual offered intriguing punctuation, puzzling spaces, and curious examples . . .
This month Keith Houston is our guide to the sometimes-forgotten (but eternally-interesting) realms of punctuation. His blog Shady Characters and its eponymous book Shady Characters: The Secret Life of Punctuation explore the history and use of the marks that make our work so readable.