The document describes the AMIDST Toolbox, an open source Java library for analyzing massive data streams using probabilistic graphical models. The toolbox uses Bayesian networks and inference algorithms like variational message passing to model and learn from continuous data streams in a scalable way. It was developed as part of an EU research project to handle real-world complex streaming data. The document outlines the toolbox's capabilities and provides an example live demo of using it to model concept drift in financial data by tracking changes over time with a hidden variable in a naive Bayes model.