Ah ha!

Max, you suggested I take a closer look at the formula in cell A1 -
I noticed that the formula looked like this: =[Book4]Sheet1!$A$1
For some reason Excel put the $'s in there on its own. My problem is solved.

On a related note, do you know of a shortcut to make a non-relative link to
a cell without manually typing in the $'s?

Thanks again,

-Fran