Churchill gradually abandoned more conventions of realism, with her loyalty to feminist themes and ideas becoming a guiding principle in her work. She won an Obie Award for best play in 1983 with Top Girls, "which deals with women's losing their humanity in order to attain power in a male-dominated environment." It features an all-female cast, and focuses on Marlene, who has relinquished a home and family to achieve success in the world of business. Half the action takes place at a celebratory dinner where Marlene mixes with historical, iconic and fictional women who have achieved great stature in a "man's world", but always at great cost. The other half of the play, set a year in the past, focuses on Marlene's family, where the true cost of her "successful" life becomes poignantly and frighteningly apparent. In Top Girls, Churchill devised a system to indicate how the dialogue should be performed. She used the forward dash signal (/) to demonstrate a person interrupting the person speaking. She also used the asterisk symbol (*) to indicate a speech following on from a speech earlier than the one immediately before it.