I have a workbook that has 150 worksheets...75 of them are summary of statements and 75 of them are details of statements. The Summary and Detail sheets keep alternating. I have been tasked to prepare a combined Summary and Combined Detail sheet. All the 75 Summary Sheets and the 75 Detailed sheets have exactly the same structure. Using SUM(Sheet 1: Sheet 150) would not work., because the detailed sheets are there in between. Can anyone suggest how to go about this? (other than reorganizing all the worksheets).