Why is Klein in front of Surnames

[mlangiano99]

Thank you for all of your help. I did read the Wikipedia page and it did help a little, but I guess I am not grasping it. If I did, I probably would not have asked the question I did above. I suspect that I am becoming an irritation with my ignorance so I will do my best to figure it out from here. I am sorry to be a bother. Thank you and Happy Holidays!