Before diving into the machine learning (ML) problems in text classification, we will take a look at the different open datasets that are available on the internet. Many of the classification tasks may require large labeled text data. This data can be broadly grouped into those with binary classes, multi-classes, and multi-labels. The following are some of the popular datasets used for benchmarking in both research and some competitions, such as Kaggle:

Some of the preceding datasets will also be used as examples for this chapter. While the preceding list is not exhaustive, these are provided for the reader so that they can start experimenting with text classification and topic categorization tasks.