Look carefully at the two attached screenshots. They were made a couple of minutes apart, and an hour or so later if I were to re-take them they would each be exactly the same.

The first screenshot was taken from my PC.
The second screenshot was taken from SWMBO's iMac.

How is it possible to have different results for the exact same search on the exact same website, but made from different computers hard-wired to the same router and cable modem?

One interesting clue is this:

PC Search URL: https://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=fatal+michael+palmer

iMac Search URL: https://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Dstripbooks&field-keywords=fatal+michael+palmer

which looks like it might be some difference in parameters of SWMBO's Amazon account.

No.

I logged into SWMBO's Amazon account from MY computer (the PC) and the search turned up the correct results, i.e., the $1.99 Kindle price. So it's not Amazon, it's something to do with SWMBO's iMac. Maybe Steve Jobs didn't like Jeff Bezos and set up this puzzle from beyond the grave.

What is going on here?

tanstaafl.