Who is Wyoming (Wyoh) Knott-Davis from The Moon Is a Harsh Mistress and what is their importance?

A tall, blonde, beautiful divorcee in her thirties, Knott is a political agitator from Hong Kong in Luna Colony. A self-styled "Fifth Internationalist," she works as a "Professional Host Mother" - a surrogate - for rich Chinese families. She is married to twins and bears a "monster" child that is destroyed. She blames it on surface exposure to a solar radiation upon arrival on the moon as a child and holds Luna Authority responsible. As a precaution, she has herself sterilized, divorces the brothers, moves to HKL, and involves herself in politics.