Pioneering outline of the concept which enhances 5G capabilities and will revolutionize the telecommunications industry Open RAN Explained details the new architectures, functionalities, and interfaces of Open RAN models and explains the standards, principles, and practical aspects the operators need to know to be prepared for the new era. The work describes the challenges and opportunities of modularization and presents scenarios and recommendations for optimal network deployment considering techno-economic aspects. It further summarizes the latest key features and aspects of the Open RAN to provide readers with a single source of information that eases network deployment, device designing, and education of personnel and students interested in advanced mobile communications. Technically, the work references the latest specifications of the O-RAN Alliance and GSMA OP/TIP, complemented by the current 3GPP Release 16 specifications on the network virtualization and spit models for which deployment is expected from 2022-25. Written by an author working at the cutting edge of 5G development in industry, sample topics covered in Open RAN Explained include: Open RAN architecture, exploring ideas like details of the requirements and challenges of the cloud runtime environment the Open RAN needs for O-Cloud RAN modularization, covering the role of 4G and 5G, 3GPP split options, O-RAN options, and hardware design O-RAN use cases, such as traffic steering, QoS and QoE optimization, massive MIMO, network slicing and service level assurance, and V2X handover Open RAN planning and deployment, regarding Open RAN deployment scenarios, service-based planning aspects, optimization, site strategies, and more Presenting many practical examples to aid in reader comprehension, Open RAN Explained is an essential and accessible resource for operators, equipment manufacturers, service providers, regulators, and educational institutes alike to understand and explore the principles and details of the Open RAN.