This chapter focused on some of the hardest challenges in data analysis in the means of cleansing data, and we covered the most important topics on missing and extreme values. Depending on your field of interest or industry you are working for, dirty data can be a rare or major issue (for example I've seen some projects in the past when regular expressions were applied to a JSON file to make that valid), but I am sure you will find the next chapter interesting and useful despite your background – where we will learn about multivariate statistical techniques.