Who is First Lieutenant Hilleboe from The Forever War and what is their importance?

First Lieutenant Hilleboe is Mandella's Second Field Officer when he is is commanding his own Strike Force. She is responsible for keeping the troops in line as well as the day-to-day operations of the company. Hilleboe is skilled at maintaining discipline, but she and Mandella do not always see eye to eye on how members of the company should be treated.