The document provides an overview of business intelligence (BI) and the extract-transform-load (ETL) process. It describes a five-layered BI architecture consisting of data source, ETL, data warehouse, end user, and metadata layers. The data source layer identifies internal and external data sources. The ETL layer extracts, transforms, and loads data. The data warehouse layer stores data in an operational data store, data warehouse, and data marts. The end user layer provides tools for users to analyze data. Metadata is managed across all layers.