SpreadsheetGear 2017 uses workbook sets to group one or more workbooks. Workbook sets may be created directly with GetWorkbookSet and used to create, read, modify, calculate and write Microsoft Excel 97-2019 and Excel for Office 365 workbooks without Excel and without any UI. Typically, each workbook view creates its own workbook set automatically.

Workbook sets created with Factory.GetWorkbookSet or Factory.GetWorkbook use the US English ("en-US") System.Globalization.CultureInfo by default. To specify the CultureInfo, use one of the Factory.GetWorkbookSet or Factory.GetWorkbook methods which takes a CultureInfo as a parameter. Workbook sets created by the Windows Forms, WPF and Silverlight WorkbookView controls create a workbook set using System.Globalization.CultureInfo.CurrentCulture.

For external cell references to work between multiple workbooks, the workbooks must be contained by the same workbook set.