Chapter 1, *Understanding Neural Networks and Deep Neural Networks*, will show us how to set up a deep learning environment to train models. The readers are then introduced to neural networks, starting from how neural networks work, what hidden layers are, what backpropagation is, and what activation functions are. This chapter uses the `keras` library to demonstrate the recipes.

Chapter 2, *Working with Convolutional Neural Networks*, will show us CNNs and will explain how they can be used to train models for image recognition and natural language processing based tasks. This chapter also covers various hyperparameters and optimizers used with CNNs.

Chapter 3, *Recurrent Neural Networks in Action*, will show us the fundamentals of RNNs with real-life implementation examples. We will also introduce LSTMs and gated recurrent units (GRUs), an extension of RNNs, and take a detailed walk-through of LSTM hyper-parameters. In addition to this, readers will learn how to build a bi-directional RNN model using Keras.

Chapter 4, *Implementing Autoencoders with Keras*, will introduce the implementation of various types of autoencoders using the `keras` library as the backend. Readers will also learn about various applications of autoencoders, such as dimensionality reduction and image coloring.

Chapter 5, *Deep Generative Models*, will show us the architecture of another method of deep neural networks, **generative adversarial networks **(**GANs**). We will demonstrate how to train a GAN model comprising of two pitting nets—a generator and a discriminator. This chapter also covers the practical implementation of variational autoencoders and compares them with GANs.

Chapter 6, *Handling Big Data Using Large-Scale Deep Learning*, contains case studies on high-performance computation involving large datasets utilizing GPUs. Readers will also be introduced to the parallel computation capabilities in R and libraries such as MXNet, which is designed for efficient GPU computing and state-of-the-art deep learning.

Chapter 7, *Working with Text and Audio for NLP*, contains case studies on various topics involving sequence data, including natural language processing (NLP) and speech recognition. The readers will implement end-to-end deep learning algorithms using various deep learning libraries.

Chapter 8, *Deep Learning for Computer Vision*, will provide end-to-end case studies on object detection and face identification.

Chapter 9, *Implementing Reinforcement Learning*, will walk us through the concepts of reinforcement learning step by step. Readers will learn about various methods, such as Markov Decision Processes, Q-Learning, and experience replay, and implement these methods in R using examples. Readers will also implement an end-to-end reinforcement learning example using R packages such as `MDPtoolbox` and `Reinforcementlearning`.