In chapter 3, *Deep Learning Fundamentals*, we gave an easy-to-understand introduction to deep learning. In the next section, *Deep networks*, we'll give a more precise definition of the key concepts that will be thoroughly introduced in the coming chapters.

# Deep learning algorithms

# Deep networks

We could define deep learning as a class of machine learning techniques, where information is processed in hierarchical layers to understand representations and features from data in increasing levels of complexity. In practice, all deep learning algorithms are neural networks, which share some common basic properties. They all consist of interconnected neurons that are organized in layers. Where they differ is network architecture...