Register in advance. While identifying family names is basic to doing genealogical research, Jewish family names are anything but simple. Different rules governed the adoption of names in different countries and in Ashkenasic and Sephardic communities. Some names were chosen, others were assigned, and some were evaded to avoid harsh consequences. They vary in origins, meanings and can have multiple spellings and grammatical forms. Names can reflect empires, border changes and emigration. Rabbinic lines have special features. Understanding Jewish naming practices can illuminate the information you gather and extend your family tree by generations.