This document discusses generative adversarial networks (GANs) which use two neural networks - a generator and a discriminator. The generator produces synthetic samples and the discriminator evaluates them as real or fake. They are trained in an adversarial process where the generator learns to produce samples that cannot be distinguished from real data, while the discriminator learns to better detect the generator's synthetic samples. GANs can generate realistic images like faces and objects and have applications such as image super-resolution, future frame prediction in videos, and image-to-image translation tasks. Training GANs requires alternating between updating the discriminator to improve detection and updating the generator to avoid detection.