macro to copy columns from one workbook to another

Hi,
I have the code below which copies columns A:C from Book1 into Book2. However, it does not work when the Book1 is not open. I would like the macro to still work when the Book1 is closed. How can I solve this problem?

Sub CopyColumnToWorkbook()
Dim sourceColumn As Range, targetColumn As Range

Set sourceColumn = Workbooks("Book1").Worksheets("Sheet1").Columns("A:C")
Set targetColumn = Workbooks("Book2").Worksheets("Sheet1").Columns("A:C")

sourceColumn.Copy Destination:=targetColumn
End Sub

Many thanks,

Please see the code in the attachement copy columns.txt