Spencer's Navajo Blanket
In the second chapter of the novel Holden visits Mr. Spencer, his old history teacher. He mentions that Spencer is wrapped up in an old Navajo blanket which he "got a big bang out of".
Recently I bought an interesting book in a second-hand shopin Albuquerque titled Navajo Blanket Weaving in Canyon de Chelly. The author is a certain Don Spencer. Now, this could of course easily be a coincidence because
a. hundreds of people have that surname and
b. Holden never mentions his teacher's first name.
However, it says in the blurb that the author "was a history teacher at a Pennsylvania school prior to his retirement in 1952".
Interestingly, the first edition of that book was printed as early as 1945; the fifth reprint – which is the one I bought – was published in 2003 with a new introduction by Tony Hillerman, the famous author of Navajo Tribal Police detective stories.
Here's another point. In the first chapter of Navajo Blanket Weaving in Canyon de Chelly (p. 27) the author relates this: The only reason why he went to the Southwest in the first place in 1930 was the climate. He wanted to do something about his grippe, which he had been suffering from for decades. (Actually, grippe is a rather old-fashioned term for a severe cold which was apparently used at the time in the US.) Then some Navajo sheepherder recommended visiting Canyon de Chelly, which is where the author fell in love with Navajo handwoven blankets and rugs.
This correlates highly with Holden's frequent remarks about Spencer's grippe. For example, when Holden asks Spencer, "How's your grippe, sir?", the teacher answers jokingly: "M'boy, if I felt any better I'd have to send for the doctor."
Merely a lot of coincidences? Quite frankly, I doubt it.