This document discusses deep learning and its applications. It provides a brief history of artificial intelligence and machine learning, noting that deep learning emerged to overcome limitations of machine learning. It describes types of machine learning like supervised, unsupervised, and reinforcement learning. Deep learning uses neural networks to focus on relevant features without much programmer guidance, helping to solve problems involving high-dimensional data like image recognition. Applications of deep learning discussed include machine translation, object classification in photos, and Google Lens.