This document provides an overview of model management techniques investigated by the author, including coupled evolution, semantic issues in bidirectional model transformations, and the MDE Forge collaborative modeling platform. It introduces model-driven engineering (MDE) and discusses how models provide abstraction and can be automated through model transformations to perform complex tasks like incremental changes and traceability management. The challenges of metamodel and model co-evolution are described, as well as approaches to manage changes across an entire MDE ecosystem. Uncertainty in bidirectional model transformations is also covered.