This subclause describes the elements and simple types that comprise the workbook main definition.

A workbook is composed of book-level properties and a collection of 1 or more sheets. The sheets are the central working surface for a spreadsheet application. The workbook part and corresponding properties comprise data used to set application and workbook-level operational state. The workbook also serves to bind all the sheets and child objects into an organized single file. The workbook properties include information about what application last saved the file, where and how the windows of the workbook were positioned, and an enumeration of the worksheets in the workbook.

It is important for the sake of simplicity to minimize the required set of workbook properties that must be present to compose a valid workbook. Therefore these are the required data points for the smallest possible (blank) workbook:

    <sheet name="Sheet1" sheetId="1" r:id="rId1"/>

Note that this workbook has a single sheet, named Sheet1. An Id for the sheet is required, and a relationship Id pointing to the location of the sheet definition is also required. Sheet1 itself will be discussed in a separate section.