I have this book on 한자 (hanja) for learners of Korean. These are Chinese characters, which are widely used in Korea, but do not form an indispensable part of the written language, unlike e.g. Japanese, where you cannot learn the written language without learning the Chinese characters too. Nevertheless, it has seemed to me that true literacy in Korean requires knowing these Chinese characters, much as an ability to understand Latin and Greek roots can aid in being well-educated in English. In fact, I have sometimes explained to my students that Latin and Greek roots are the English language's hanja.
Therefore, I'm going to try to learn some. But at the moment, I can't even figure out how to type them – I know there should be some kind of "type in hangeul and look up appropriate hanja" functionality on my Korean keyboard gadget on my laptop, but I can't get it to work. So, I'll let you know when I get it to work.
Meanwhile, we're having some freezing rain, and, knock-on-wood, the flu I've had seems to be getting a little better.