This document defines big data and discusses its importance. It describes big data as large datasets that are difficult to manage with traditional tools due to their volume, variety, and velocity. Examples are provided of how governments and private sector organizations like Walmart and Facebook generate and use big data. The phases of big data analysis and challenges like heterogeneity are outlined. Technologies used for big data from companies like Oracle, Microsoft and IBM are listed. Opportunities big data provides for driving revenue, understanding customers, and improving operations are discussed. The document concludes with other aspects of big data like its impact on knowledge and transparency.