Now, all white blood cells, or generally speaking, white blood cells, can actually differentiate into many different types of specialized white blood cells, as we'll see in just a moment. And all these specialized white blood cells have their own unique purpose and function. So let's begin by taking a look at the following flowchart, which basically describes the different types of categories of leukocytes. So generally, we can divide leukocytes into these three categories. We have granulocytes, agranulocytes and megacaryocytes. And then we can even further subdivide all these categories and we'll discuss that in just a moment.