What is the fine-grained topic of the following text: As part of the series of posts announced at this initial blog post (.NET Application Architecture Guidance) that explores each of the architecture areas currently covered by our team, this current blog post focuses on introducing the new "Modernize existing .NET applications with Windows Containers and Azure" eBook which you can download here. Only return the topic.
Introduction to the "Modernize existing .NET applications with Windows Containers and Azure" eBook