In this chapter, we learned about text classification methods and their implementation in R language. We learnt how to use classifiers to build applications such as spam filter, topic models, and so on. We also looked into the model evaluation and validation methods. In the coming chapters, we will take up more practical examples to utilize the tools and knowledge gained in the previous chapters to mine and extract insights from social media. We will also look into different distributed text mining methods to help applications build in R to scale up for high dimensional data.