I would like to have a list of all sheet names in a workbook appear in a data validation list without using VBA. I was trying to define a name, sheets, with =GET.WORKBOOK(1), which per MS help should return the names of all sheets in the workbook, as a horizontal array of text values, but when I add =sheets to the list source in data validation, it returns an error (The Source currently evaluates to an error. Do you want to continue?). Does anyone have any ideas?