Windows Failover Clustering (WFC) is one of the oldest technologies utilized by Windows Server for the high availability of systems and services, whether that be traditional on-premise IT infrastructures or hybrid and multi cloud infrastructures in Microsoft Azure. Failover clustering and other relevant Microsoft technologies such as Always On Availability Groups are in many cases the cornerstone of a resilient and solid infrastructure design. In various real life scenarios however, administrators come across incidents and issues in their Windows failover clustering infrastructure which have a significant impact on business operations and may incur catastrophic downtime for services offered to customers. This handbook aims to consolidate all Microsoft and third party vendor best practices for Microsoft Windows Failover Clustering which can be applied in both host cluster and guest cluster scenarios. Building an efficient and error-free failover cluster encompasses concepts and design considerations from more than one areas, including the Windows Server operating system, Software Defined (SD) and Hyper-converged infrastructure (HCI) concepts as well as storage and IP networking design principles. The book takes a pragmatic hands-on approach by presenting the theoretical foundations of the inner workings of a failover cluster architecture, discusses the most frequent failover clustering usage scenarios and concludes with practical applications and sample scripts for auditing and health checking an existing cluster as well as for building a new cluster in an automated and consistent way.