I'm quite positive you cannot set any type of object outside of a sub/function

Here is something that offers a few different ways of setting either
WorkBooks, WorkSheets or a Range

Public Sub test()
   
   Dim aBook As Workbook
   Dim aSheet As Worksheet
   Dim aRange As Range
   
   
   Set aBook = Workbooks("Book1")
   Set aSheet = Workbooks("book1").Sheets("Sheet1")
   Set aRange = Workbooks("Book1").Sheets("Sheet1").Range("A1:A10")
   aBook.Sheets("Sheet1").Cells("1, 5") = "Funkah"  
   aSheet.Cells(1,3).Value = "Rar"
   aRange.value = "Test"
   
End Sub

It's all pretty much straight forward, but makes it all that easier to
shrink down certain calls.

Hope this helps somewhat! :)

Nate

You can declare the workbook variable outside of the procedure, but you have
to load it from within a procedure.

You can put the code in the Workbook_Open procedure in the ThisWorkbook code
module (it must be in ThisWorkbook, not some other module).

Private Sub Workbook_Open()
   On Error Resume Next
   Set myBook = Workbooks("Test.xls")
   If Err.Number <> 0 Then
       ' Test.xls not found. do something
   Else
       ' Test.xls found. do something.
   End If
End Sub

Next, declare the myBook variable in a regular code module (not in
ThisWorkbook).

Public myBook As Excel.Workbook