This chapter highlight the core concepts of my research area. It includes the introduction of Big Data, Big Data in medical field, Diabetic Mellitus, Big data analytics, Predictive analytics. More over it also introduce Cloud computing, Hadoop technology with MapReduce and Machine Learning techniques along with Data Mining and knowledge discovery. It also includes problem identification and deciding the statement of the problem with significance and objective of the research. At the end of the chapter, chapter scheme of thesis organization is given. Big Data All people in this era are becoming more techno savvy and use of electronic device is increasing day by day. Data is growing in tremendous way out of our imagination reach. The term Big Data refers to all the data that is generated across the world. Main sources of such big data are Media, Cloud, Web, IOT and Databases. This data may be in structured or unstructured form. Figure 1.1 shows the various sources of the big data.