Lightly grease 8 or 9-inch square pan. Using half the cookies, arrange single layer of cookies side by side over bottom of greased pan.
In small saucepan, melt caramels with milk over low heat, stirring occasionally until blended and smooth. Spread evenly over cookie layer in pan. Arrange remaining wafer cookies side by side in single layer over caramel.
In small saucepan, melt chocolate chips with butter over low heat, stirring occasionally. Spread evenly over wafer cookies. Cool until set and cut into bars.