The key property of models@run.time systems is their use and provision of manageable reflection, which is characterized to be tractable and predictable and by this overcomes the limitation of reflective systems working on code, which face the problem of undecidability due to Turing-completeness. To achieve tractability, they abstract from certain aspects of their code, maintaining runtime models of themselves, which form the basis for reflection. In these systems, models form abstractions that neglect unnecessary details from the code, details which are not pertinent to the current purpose of reflection. Thus, models@run.time systems are a new class of reflective systems, which are characterized by their tractability, due to abstraction, and their ability to predict certain aspects of their own behavior for the future. This chapter outlines a reference architecture for models@run.time systems with the appropriate abstraction and reflection components and gives a roadmap comprised of short-and long-term research challenges for the area. Additionally, an overview of enabling and enabled technologies is provided. The chapter is concluded with a discussion of several application fields and use cases.