Data mining is the process of automatically discovering patterns and trends in large datasets. It involves defining problems, gathering and preparing data, building and evaluating models, and deploying knowledge. Common data mining techniques include association, classification, clustering, prediction, sequential patterns, and decision trees. These techniques can be combined and applied to domains like marketing, banking, healthcare, and more to analyze customer behavior, identify fraud, and make predictions. While data mining can find hidden patterns, it requires domain expertise and cannot determine the value of information or replace the need to understand business needs and data.