This paper describes a recently-released, structural and composable modeling system called the Liberty Simulation Environment (LSE). LSE automatically constructs simulators from system descriptions that closely resemble the structure of hardware at the chosen level of abstraction. Component-based reuse features allow an extremely diverse range of complex models to be modeled easily from a core set of component libraries. This paper also describes a set of such libraries currently under development. With LSE and these component libraries, students will be able to learn about systems in a more intuitive fashion, researchers will be able to collaborate with each other more easily, and developers will be able to rapidly and meaningfully explore novel design candidates.