It is one of the basic concepts of Object Oriented Programming. You only need to know that it is the type required for a parameter to a function or what operations are available on the type. Notice that those names do not use Hungarian. This is very useful in languages that don't keep track of types information for you. Thus, the notation simply adds to obscurity.
Hungarian notation is, when all is said and done, a commenting technique.
And the one great law of comments is that they lie. Comments are not syntax checked, there is nothing forcing them to be accurate. And so, as the code undergoes change during schedule crunches, the comments become less and less accurate. The same happens with hungarian notation. When the type of a variable changes, it is not likely that you are going to hunt through all the code and change all occurrences of its name.