The document discusses Microsoft's Cognitive Toolkit (CNTK), an open source deep learning toolkit developed by Microsoft. It provides the following key points:
1. CNTK uses computational graphs to represent machine learning models like DNNs, CNNs, RNNs in a flexible way.
2. It supports CPU and GPU training and works on Windows and Linux.
3. CNTK achieves state-of-the-art accuracy and is efficient, scaling to multi-GPU and multi-server settings.