This thesis describes the vision of I-centric communications -a new paradigm for future telecommunication systems. The main objective of this approach is to consider the human communication behavior, not the technologies that support communication, as the starting point for the design of telecommunication systems. The focus of this thesis is on the conceptual integration of all aspects of I-centric communications.Looking at the communication behavior of human, it is obvious, that human beings frequently interact with a set of objects in their environment. Following this view, a new approach is not to build communication systems based on specific technologies, but on the analysis of the individual communication space.The result is a communication system that adapts to the demands of each individual (I-centric). The communication system will act on behalf of human's demands, reflecting recent actions to enable self-adaptation. I-centric Services adapt to individual communication spaces and situations. In this context 'I' means I, or individual, 'Centric' means adaptable to I requirements and the individual's environment.The rationales above require intelligence in service provisioning in order to personalize, adapt to situational and environmental conditions, to monitor and to control the individual communication space. An I-centric communications system will provide the intelligence required for modeling the communication space of each individual adapting to its interests, environment, and preferences.The thesis introduces the vision of I-centric communications, followed by the development of a reference model for I-centric communications. Since both, the vision and the reference model, are general, an architectural framework for I-centric communications is introduced later on. This framework is used to design and implement an I-centric communications system.The work in the area of I-centric communications was carried out in cooperation of the Department for Open Communication Systems (OKS) at the Technical University Berlin (TUB) and the Fraunhofer Institute FOKUS. The vision and the reference model, introduced in this thesis, are the results of this cooperation.The main research directions for the cooperation between TUB and FOKUS have been a general model for I-centric Services, the service platform for I-centric Services, and an approach for the interaction of users with I-centric Services.This thesis focuses on I-centric Services and according communication system. The aspects of user interaction are out of scope of this thesis. Nevertheless, these aspects have been analyzed by Stephan Steglich, researcher at the TUB, in a second PhD thesis in parallel.The results of this thesis have been contributed to different national and international projects (BMBF: LiveFutura, VHE, PI-AVIda, IST: WSI, WWRI), standardization bodies (OMG, WWRF), conference papers, and journals by introducing the vision of I-centric communications to a larger auditorium, and by exploiting parts of the developed I-centric systems....