`<workbook>` (Workbook)

This element is the root part of the workbook in SpreadsheetML. It defines the structure of the workbook:

Sheets: represents the collection of worksheets in the workbook. The worksheet is the primary document that you use to store and work with data.
Views: SpreadsheetML defines a collection of Workbook views that define basic window dimensions and position of the workbook. It also defines a collection of Custom Workbook Views that allow the end-user to define a series of rich views on their workbook data. Users can create more than one view of the same workbook without saving separate copies of the workbook.
Properties: the workbook has several property collection that store basic workbook settings, such as the date system to use, file protection settings, calculation settings, and smart tag behaviors.
Names: represent descriptive that represent cells, ranges of cells, formulas, or constant values.

example:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<workbook xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/5/main" 
mlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships">
  <fileVersion lastEdited="4" lowestEdited="4" rupBuild="4017"/>
  <workbookPr date1904="1" vbName="ThisWorkbook" defaultThemeVersion="123820"/>
  <bookViews>
    <workbookView xWindow="120" yWindow="45" windowWidth="15135"
      windowHeight="7650" activeTab="4"/>
  </bookViews>
  <sheets>
    <sheet name="Sheet1" sheetId="1" r:id="rId1"/>
    <sheet name="Sheet2" sheetId="2" r:id="rId2"/>
    <sheet name="Sheet5" sheetId="3" r:id="rId3"/>
    <sheet name="Chart1" sheetId="4" type="chartsheet" r:id="rId4"/>
  </sheets>
  <definedNames>
    <definedName name="MyDefinedName">Sheet3!$A$1:$C$12</definedName>
  </definedNames>
  <calcPr calcId="122211" calcMode="autoNoTable" refMode="R1C1" iterate="1"
    fullPrecision="0"/>
  <customWorkbookViews>
    <customWorkbookView name="CustomView1" 
      guid="{CE6681F1-E999-414D-8446-68A031534B57}" maximized="1" xWindow="1" 
      yWindow="1" windowWidth="1024" windowHeight="547" activeSheetId="1"/>
  </customWorkbookViews>
  <pivotCaches>
    <pivotCache cacheId="0" r:id="rId8"/>
  </pivotCaches>
  <smartTagPr embed="1" show="noIndicator"/>
  <smartTagTypes>
    <smartTagType namespaceUri="urn:schemas-openxmlformats-org:office:smarttags" 
      name="date"/>
  </smartTagTypes>
  <webPublishing codePage="1252"/>
</workbook>

Parent Elements
Root element of SpreadsheetML Workbook part

Child Elements	Subclause
`<bookViews>` (Workbook Views)	§3.2.1
`<calcPr>` (Calculation Properties)	§3.2.2
`<customWorkbookViews>` (Custom Workbook Views)	§3.2.4
`<definedNames>` (Defined Names)	§3.2.6
`<externalReferences>` (External References)	§3.2.9
`<extLst>` (Future Feature Data Storage Area)	§3.2.10
`<fileRecoveryPr>` (File Recovery Properties)	§3.2.11
`<fileSharing>` (File Sharing)	§3.2.12
`<fileVersion>` (File Version)	§3.2.13
`<functionGroups>` (Function Groups)	§3.2.15
`<oleSize>` (Embedded Object Size)	§3.2.16
`<pivotCaches>` (PivotCaches)	§3.2.18
`<sheets>` (Sheets)	§3.2.20
`<smartTagPr>` (Smart Tag Properties)	§3.2.21
`<smartTagTypes>` (Smart Tag Types)	§3.2.23
`<webPublishing>` (Web Publishing Properties)	§3.2.24
`<webPublishObjects>` (Web Publish Objects)	§3.2.26
`<workbookPr>` (Workbook Properties)	§3.2.28
`<workbookProtection>` (Workbook Protection)	§3.2.29

The following XML Schema fragment defines the contents of this element:

<complexType name="CT_Workbook">
	<sequence>
	<element name="fileVersion" type="CT_FileVersion" minOccurs="0" maxOccurs="1"/>
	<element name="fileSharing" type="CT_FileSharing" minOccurs="0" maxOccurs="1"/>
	<element name="workbookPr" type="CT_WorkbookPr" minOccurs="0" maxOccurs="1"/>
	<element name="workbookProtection" type="CT_WorkbookProtection" minOccurs="0" maxOccurs="1"/>
	<element name="bookViews" type="CT_BookViews" minOccurs="0" maxOccurs="1"/>
	<element name="sheets" type="CT_Sheets" minOccurs="1" maxOccurs="1"/>
	<element name="functionGroups" type="CT_FunctionGroups" minOccurs="0" maxOccurs="1"/>
	<element name="externalReferences" type="CT_ExternalReferences" minOccurs="0" maxOccurs="1"/>
	<element name="definedNames" type="CT_DefinedNames" minOccurs="0" maxOccurs="1"/>
	<element name="calcPr" type="CT_CalcPr" minOccurs="0" maxOccurs="1"/>
	<element name="oleSize" type="CT_OleSize" minOccurs="0" maxOccurs="1"/>
	<element name="customWorkbookViews" type="CT_CustomWorkbookViews" minOccurs="0" maxOccurs="1"/>
	<element name="pivotCaches" type="CT_PivotCaches" minOccurs="0" maxOccurs="1"/>
	<element name="smartTagPr" type="CT_SmartTagPr" minOccurs="0" maxOccurs="1"/>
	<element name="smartTagTypes" type="CT_SmartTagTypes" minOccurs="0" maxOccurs="1"/>
	<element name="webPublishing" type="CT_WebPublishing" minOccurs="0" maxOccurs="1"/>
	<element name="fileRecoveryPr" type="CT_FileRecoveryPr" minOccurs="0" maxOccurs="unbounded"/>
	<element name="webPublishObjects" type="CT_WebPublishObjects" minOccurs="0" maxOccurs="1"/>
	<element name="extLst" type="CT_ExtensionList" minOccurs="0" maxOccurs="1"/>
	</sequence>
</complexType>

<workbook> (Workbook)

`<workbook>` (Workbook)