The document discusses leveraging big data in legacy data warehouses. It introduces Harro M. Wiersma, a big data expert, and outlines some of the challenges with traditional data warehouses, including inflexibility and multiple sources of data. The document then presents the concept of a big data data warehouse (bDWH), which aims to simplify infrastructure and bring big data into the existing warehouse to gain a 360-degree view of customers and businesses by leveraging various new sources of data.