PyTorch is a popular open-source deep learning framework used for building neural networks and AI models. It provides dynamic computation graphs, easy debugging, and GPU acceleration, making it ideal for both research and production. Beginners should start with tensors, autograd, and basic neural network layers, then progress to building models for tasks like image classification, natural language processing, and reinforcement learning. PyTorch also integrates seamlessly with Python libraries like NumPy and supports frameworks such as TorchVision and TorchText. Learning PyTorch empowers developers to create efficient and scalable AI applications.