Looker Studio (formerly Google Data Studio) is a free, cloud-based business intelligence and data visualization platform from Google that transforms data from multiple sources into customizable, interactive dashboards and reports. It connects to over 800+ data sources through native and community connectors, enabling real-time data analysis without requiring SQL knowledge. The tool's drag-and-drop interface makes it accessible to both technical and non-technical users, while its sharing and embedding capabilities allow teams to collaborate on data-driven insights. Understanding Looker Studio's data source layer (where transformations happen) versus its visualization layer (where formatting happens) is crucial — calculated fields created at the data source level are reusable across all reports, while chart-level fields apply only to that specific visualization.