[MUSIC] Classifiers have really changed the world. Today we take classifiers for granted but they're at the core of every piece of technology that we enjoy. Be it the spam filters we talked about, dealing with our email, what happens when you type on the web search and get a particular set of answers back, what odds get shown to you, what products get recommended and how we classify somebody's medical conditions and more. And we see that all over the world, happening everyday. And interesting thing about classifiers, is that the fundamental techniques that you need to build a classifier, are very similar to those that you need to build all other sorts of machine leaning that models. And so, if you really understand classifiers in depth, you'll be able to do basically all kinds of machine learning, what's called supervised learning. And that's in the core of most real world applications of machine learning today. [MUSIC]