This book provides a timely and comprehensive overview of the introduction of LTE technology for PPDR communications. It describes the operational scenarios and emerging multimedia and data-centric applications in demand and discusses the main techno-economic drivers that are believed to be pivotal for an efficient and cost-effective delivery of mobile broadband PPDR communications. The capabilities and features of the LTE standard for improved support of mission-critical communications (e.g., proximity services, group communications) are covered in detail. Also, different network implementation options to deliver mobile broadband PPDR communications services over dedicated or commercial LTE-based networks are discussed, including the applicability of the Mobile Virtual Network Operator (MVNO) model and other hybrid models. Radio spectrum matters are also discussed in depth, outlining spectrum needs and providing an outlook into allocated and candidate spectrum bands for PPDR communications and suitable dynamic spectrum sharing solutions in PPDR communications. Explanations are accompanied by a vast collection of references that allow the more intrigued reader to gain further insight into the addressed topics.