Update Windows 11 Security Book link and add section on mission-critical application safeguards

windows/security/introduction.md

@@ -4,10 +4,10 @@ description: System security book.
 ms.date: 09/01/2023
 ms.topic: tutorial
 ms.author: paoloma
-ms.collection: 
+ms.collection:
   - essentials-security
   - essentials-overview
-content_well_notification: 
+content_well_notification:
   - AI-contribution
 author: paolomatarazzo
 appliesto:
@@ -57,4 +57,6 @@ Microsoft offers comprehensive cloud services for identity, storage, and access
 
 ## Next steps
 
-To learn more about the security features included in Windows 11, download the [Windows 11 Security Book: Powerful security from chip to cloud](https://aka.ms/Windows11SecurityBook).
+To learn more about the security features included in Windows 11, read the [Windows 11 Security Book](book/index.md).
+
+<!--(https://aka.ms/Windows11SecurityBook).-->

windows/security/toc.yml

@@ -1,6 +1,8 @@
 items:
 - name: Introduction to Windows security
   href: introduction.md
+- name: Windows 11 security book 🔗
+  href: book/index.md
 - name: Security features licensing and edition requirements
   href: licensing-and-edition-requirements.md
 - name: Security foundations