My workbook contain 13 sheets. One sheet for each month (January thru December) plus one sheet to be ale to run totals. I can easily use =Sum(January:December!B2) to calculate the sum of all B2 cells in sheets January thru December. However, i want the ability to select the range of sheets based off of cell A1 (which will have the desired beginning month) and cell A2 (which will have the desired ending month). Please Help !