It was four o'clock when Bobs descended from a taxicab and mounted the steps of a handsome brown stone mansion on Riverside Drive. Mr. Van Loon was at home and, being a most kindly old gentleman and accustomed to receiving all manner of persons, he welcomed Roberta into his wonderful library, listened courteously at first, but with growing interest, when he realized that this radiant girl had a book to sell which she believed to be both rare and valuable. The eyes of the cultured gentleman plainly revealed his great joy when he actually saw the long-sought first volume.