Hello all, I am using C# to manipulate data from an Excel spreadsheet with some success. At the moment i am using Excel.Application ExcelObj = new Excel.Application(); Excel.Workbook theWorkbook = ExcelObj.Workbooks.Open(filename, 0, false, 5, "", "", true, Excel.XlPlatform.xlWindows, "\t", false, false, 0, true, 0, 0); which opens Excel and the worksheet specified by filename. Is it possible to manipulate an Excel spreadsheet that is already open rather than opening it within the program? Cheers