If you need to directly read from or write to a workbook from VBA, you must open the workbook. Excel formulas in the worksheet can have external references to other workbooks which don't require the workbooks to be open. One alternative might be to put formulas in the workbook someplace that refer to other workbooks, and have the code refer to those values. Another alternative would be to use the code to write those formulas, then read the resulting values (I have never tried this but I can't imagine why it wouldn't work).

By the way I have a small comment on your code. Using Workbook as a variable name is not advisable because Workbook is also a class name in Excel VBA. Although it will work it can get very confusing in some situations. An alternative here might be WorkbookName. Also
[code]
Workbook = "R:\hLog\" & "hLog" & ".xlsm"
' Any reason you didn't do this:
Workbook = "R:\hLog\hLog.xlsm"
[code]