The document provides an overview of convolutional neural networks (CNNs) and their layers. It explains that CNNs take advantage of the 2D structure of input images through the use of convolutional layers, pooling layers, and fully-connected layers. Convolutional layers apply filters to local regions of the input volume to identify patterns instead of individual pixels. Pooling layers perform downsampling to reduce the spatial size of representations. The document provides examples of convolutional filters and how they are applied to an input through sliding and striding operations.