Understanding Azure - A Guide For Developers - An Official eBook Guide from Microsoft
Microsoft has released the latest Developers Guides on Azure eBook –. It covers the latest Azure platform services such as Azure Functions, Azure Service Fabric and Azure IoT application development. It's FREE and you can get it from the link below. It's a very good resource for developers who want to learn and keep up with the latest Azure technologies and best practices!
Azure_Developer_Guide_eBook.pdf
more free ebooks around Azure
Developing big data solutions on Microsoft Azure HDInsight – eBook
Microsoft Azure Essentials - Fundamentals of Azure
Microsoft Azure Essentials – Migrating SQL to Azure
Microsoft Azure Essentials: Azure Machine Learning
Planning and Preparing for Microsoft SharePoint Hybrid
The Security Development Lifecycle
Microsoft System Center Data Protection for the Hybrid Cloud
any my favorite 
TCP/IP Fundamentals for Microsoft Windows
Full ebook Gallery around Microsoft Technologies can be found here
Free ebooks from the MVA Academy here