CurtTheGamer

It says "The Sign of *the* Four." It's certainly possible that the correction was exclusive to this edition, but B&N in general kind of is hit-and-miss with their publications of classics (even their Sherlock Holmes edition has a few misspellings here and there). But, on the other hand, they do appear to make a conscious effort to actually "fix" things in quite a few cases. Off the top of my head, their publication of the Ewing translation of The Nutcracker corrects the one mistake towards the end where the protagonist is called "Mary" when she's called "Marie" through the entire rest of the book (they've corrected it so that it says "Marie" there), their edition of The Complete Grimms' Fairy Tales uses the Margaret Hunt translation for all the stories except for one story (The Golden Goose), which uses the Lucy Crane translation instead (which seems to indicate to me that somebody in the publishing company must have known that Hunt shortened that story for some reason, and so sought out a more accurate translation of that particular story to put into the book, though, on the other hand, they also have a smaller edition of Grimms' Fairy Tales that uses the notoriously inaccurate Edgar Taylor translation), and they also have certain title names/character names changed to their more traditional ones when compared to how Hunt translated them (eg. "Little Red Cap" is retitled "Little Red Riding Hood" for the B&N edition). And of course, using the original opening for The Resident Patient rather than the altered one (though this could have simply been on accident as the text file/source text that they used might have had the original already). It's all highly interesting.

The Barnes and Noble edition actually corrects this so that the letter says "September 7" instead. I sort of wonder whether this correction was made solely by this publisher, or if there does exist some kind of earlier text edition that does the same thing.

Interestingly enough, my copy of The Complete Sherlock Holmes (the Barnes and Noble edition) actually does include The Cardboard Box as part of His Last Bow rather than as part of Memoirs, but it still includes the original version of The Resident Patient without the duplicate section from The Cardboard Box. I remember being so confused by this back when I read the books in my spare time back in my school years, as the copies in the school library had the butchered version of The Resident Patient. At the time, I just assumed that maybe that the canon explanation was that Dr. Watson was throwing random events from his notes into stories where they didn't necessarily happen at that time, and accidentally put this one into two separate stories. I found out the real explanation with a bit of Googling shortly afterwards. When I bought the Barnes and Noble edition back a month or so ago, this was actually the very first thing I checked in the book. I was kind of disappointed that they placed The Cardboard Box as part of His Last Bow, but very happy that it had the original version of The Resident Patient. The former is a minor point as I can easily flip to Cardboard Box and read that it the order it should be placed in. The latter is the more important point.