I hope the old doctor took for appreciation the smile that played upon my face as I contrasted his pitiful offering with the endless miles of book stacks in the libraries of the outer world where I had spent so many of my earlier days. "Our books are safer here," said Zimmern, "for no one would suspect a girl on this level of being interested in serious reading. If perchance some inspector did think to perform his neglected duties we trust to him being content to glance over the few novels in the case outside and not to pry into her wardrobe closet. There is still some risk, but that we must take, since there is no absolute privacy anywhere. We must trust to chance to hide them in the place least likely to be searched." "And how," I asked, "are these books accumulated?" "It is the result of years of effort," explained Zimmern. "There are only a few of us who are in this secret group but all have contributed to the collection, and we come here to secure the books that the others bring. We prefer to read them here, and so avoid the chance of being detected carrying forbidden books. There is no restriction on the callers a girl may have at her apartment; the authorities of the level are content to keep records only of her monetary transactions, and that fact we take advantage of. Should a man's apartment on another level be so frequently visited by a group of men an inquiry would be made." All this was interesting, but I inferred that I would again have opportunity to visit the library and now I was impatient to keep my appointment with Bertha. Making an excuse for haste, I asked Zimmern to get the geography for me. The stiff back of the book had been removed, and Zimmern helped me adjust the limp volume beneath my waistcoat. "I am sorry you cannot remain and meet Marguerite tonight," he said as I stepped toward the door. "But tomorrow evening I will arrange for you to meet Colonel Hellar of the Information Staff, and Marguerite can be with us then. You may go directly to my booth in the cafe where you last dined with me." ~4~ After a brief walk I came to Bertha's apartment, and nervously pressed the bell. She opened the door stealthily and peered out, then recognizing me, she flung it wide. "I have brought you a book," I said as I entered; and, not knowing what else to do, I went through the ridiculous operation of removing the geography from beneath my waistcoat. "What a big book," exclaimed Bertha in amazement. However, she did not open the geography but laid it on the table, and stood staring at me with her child-like blue eyes. "Do you know," she said, "that you are the first visitor I ever had in my apartment? May I show you about?"