The service sector has experienced rapid growth in the modern era. As service offerings gain more relevance, businesses and companies need to adapt with their new service centered offerings with the new (dominant) logic adopted, that is, the Service dominant logic (SDL). This dominant logic proposes that service as application of knowledge and skills is the fundamental basis of economic exchange. In this modern era, the stakeholders’ role is also very important to create value while interacting through collaboration in an interactive configuration, which is called service systems. The mutual exchange between these service systems co-creates value for each other and is examined through a study called service science. Service systems’ structure is dynamic over time and its value can be defined as the improvement of the system state, which can be measured by its fitness in the surrounding environment. Therefore, value co-creation between service systems can create changes inside the system. To manage the complexity of interactions between service systems, the discipline of service management is needed. Service management is rooted in the systemic understanding of value creation. Service management aims to orchestrate and govern service systems and encompasses services such as encounters, quality, customer relationships, and organizational capabilities. Service management also addresses the dynamic capabilities of service systems. This chapter aims to provide a better understanding of these foundational concepts and explores the concept of service systems through its components, characteristics, and types. This chapter explores service systems as complex adaptive systems and examines the value co-creation process inside service systems. Furthermore, this chapter also provides the theoretical framework and models that are related to service systems. Last, this chapter provides management challenges and future directions regarding the current service studies.