sentences:  In 1953, Carl announced that he would form the "World's Largest Bookstore" the following year by merging the separate Kroch's and Brentano's bookstores and by enlarging the space that was then occupied by Brentano's at 29 South Wabash Avenue to 40,000 square feet of retail space.In the basement of this store was another store that was called "Super Book Mart" which specialized in carrying paperbacks and low cost hardback reprints, the first of its kind in Chicago.Kroch's and Brentano's was said to have the finest selection of art books in the region, and its sales clerks were famously knowledgeable.