This dissertation questions the common assumption that e-learning requires a "learning management system" (LMS) such as Moodle or Blackboard. Based on an analysis of the current state of the art in LMSs, we come to the conclusion that the functionality of conventional e-learning platforms consists of basic content management and communications facilities (such as forums, chats, wikis, etc.) and functionality for assessment (such as quizzes). However, only assessment functionality is actually specific to e-learning. Furthermore, the content management and communication functionality in e-learning platforms is typically restricted and often inferior when compared with the more general implementations available in Web content management systems. Since content management systems (CMS) offer more general and more robust functions for managing content, we argue that e-learning platforms should be based on content management systems. Only assessment functions are actually specific to e-learning and need to be added to a CMS; this requires the architecture of the CMS to be modular. As a proof of concept, we have designed and implemented the eduComponents, a component-based e-learning system architecture, realized as software components extending a general-purpose content management system with facilities for course management and assessment. The eduComponents have been successfully used since several semesters at Otto von Guericke University and other institutions. The experience with the eduComponents gives practical evidence for the theses we have put forward in this dissertation and of the feasibility of the eduComponents approach. The research done for this dissertation has also resulted in practical definitions for "e-learning" and "e-learning platform," terms which are notoriously ill-defined. Based on these definitions, we have developed an innovative way to assess and to visualize the areas of functionality of e-learning environments. A glossary, student questionnaire, user questionnaire, and bibliography are included. Individual chapters contain footnotes. (Contains 52 figures and 6 tables.)