OK, guys, LR is teaching me humility. I have 37 files in a folder named: Dolly Madison. In Library, Grid mode, the left panel says 36/37. the "missing file" is named IMG_1204.CR2. To the left of it I have IMG_1203.CR2 and to the right of it I have IMG_1205.CR2. All filters are turned off and I have tied to (both) select all and select none under the EDIT pull-down menu. Quiting out of LR and then starting it again does not make a difference.
I was messing around and clicked some unknown key or menu command combination and did this to myself, but I know not how. ("Messing Around" is an informal term for: "Learning by Doing")
I tried to reimport from current location, but it says the file is already in my Library. Just plain baffled here. Does anybody know why this file is hidden and how to unhide it?
OK GUYS - I FOUND IT. SOMEHOW SET IT INTO A "STACK" UNSTACK IT AND VOILA!