Machine learning is a subset of artificial intelligence that allows systems to learn and improve from experience without being explicitly programmed. It builds mathematical models from sample data to make predictions or decisions. Machine learning algorithms are used widely in applications like email filtering and computer vision. It can help businesses unlock value from their data and make more competitive decisions. There are several types of machine learning including supervised, unsupervised, and reinforcement learning. Popular tools include Scikit-Learn, TensorFlow, and PyTorch. Languages used include Python, C++, and R. Machine learning has applications in manufacturing, retail, healthcare, travel, finance, and energy.