Korean names usually have three parts: the family or surname placed first, and a name identifying the generation, alternating each generation to second or third place with th given personal name. Example: Suh Byung-su and his brother Suh Byung-min are from the Byung generation while their father Suh In-sok is from the Sok generation.
There are only around 200 family names in Korea and the five most frequent - Kim Pa(r)k, Yi (Lee), Choi (Choe) and Oh - cover about 70 percent of the population. Because of the inconsistencies of translating names from Hangul to Roman characters, spellings of these names vary. For instance, Yi is also spelled in English as Lee and Rhee.
Fortunately, Asians exchange business cards upon meeting, so you can refer to them to keep separate in your mid the three Misters Kim you'll meet at one party. Be prepared to hand over your card.
Korean women keep their maiden names after marriage and do not assume their husbands' surname. Children carry their father's surname.
Family names are traditional clan names and each has a village from which it comes. Thus, there is a difference between Kim who comes from Kwong-ju and Kim who comes from Kimhae.
If at all possible, Koreans avoid calling a person directly by his name. Instead they use his title, position, trade, profession, scholastic rank or some honorific form such as "teacher." Parents often are addressed as the equivalent of "Jimmy's mommy" or "Susie's daddy," rather than "Mrs. Kim."