So, as we have a grip on the basic concepts of Observables and Observers by now, let's move to something more interesting and advanced. The Observables that we are talking all about can be categorized into two categories based on their behavior. As the heading suggests, the two categories are Hot Obervables and Cold Observable. I can bet that, by now, you are craving to know more about Hot and Cold Observables, aren't you? So, let's dive into it.