Heat The Olive Oil In A Large Skillet Over Medium-High Heat. Season The Chicken Breasts With Salt And Pepper. Place Chicken In The Skillet, And Cook Until Browned On Each Side, About 5 Minutes Per Side. Reduce Heat To Medium, And Add The Butter And Garlic. Saute For About 3 Minutes. Pour In The Gin, Vermouth, Lemon Juice, And Olives; Simmer For 5 To 10 Minutes, Until The Sauce Thickens And Chicken Juices Run Clear.