THE Austrian National Library in Vienna contains, among other things, 2.6 million books. If you passed out one to each resident in this capital, there'd be about 1 million left over. Gerhard Roth, in his recently published "Journey to the Center of Vienna," calls the library a "book mine," referring, I imagine, to both its underground storage capacities and its potential as a source of raw material.Take the bookplate collection, as exhaustive as it is esoteric. I heard about it from one of my professors, who cited, if I recall correctly, a number close to 50,000. This turns out to have been guesswork, as Frau Doktor Galosy, the "ex libris" curator, herself doesn't even know the exact figure. But my professor was right about there being a lot, which is logical, considering all the books. I called Frau Doktor Galosy not long ago to set up a visit, just out of curiosity. Carrying, as the expression goes, coals to Newcastle, I seized the opportunity to bring along five recently acquired bookplates of my own, which are printed together with this article. At the appointed hour I made my way up the vestibule stairway, the walls of which are decorated with Roman gravestones from the second and third centuries. In passing, it struck me suddenly that they are set into the walls in a manner not unlike that in which an ex libris is pasted into the front of a book. In a similar fashion, they too have outlived their original functional purpose, becoming an artistic end in themselves. Frau Doktor Galosy's office is small, like herself, and smells of hand lotion. It has flagstone floors, and a window at one end brings in light, though it doesn't seem to be a view to anything at all, like a false backlit window on a stage. This room of hers is in the part of the library that formerly belonged to the adjacent Augustine monastery, and the visitor soon realizes that it used to be a monk's cell. It dawned on me less quickly that the half dozen oak cabinets lining both sides of the tiny chamber hold the collection. They leave only enough space for a desk (covered with papers), a small table (ditto), and two chairs (one of which was stacked high with books). Several times when Frau Doktor Galosy handed me an ex libris from one of the cabinets I stood up from the then-bookless chair, but each time she patiently requested that I sit back down, as there really was no room for both of us to be on our feet at once. The cabinets along the left-hand wall, I learned, are neatly arranged inside with clever folders of acid-free paper holding organized and inventoried ex libris. Frau Doktor Galosy ardently plucked out two that she thought might interest me: one of Rainer Maria Rilke's and one of Paul Wittgenstein's (Ludwig's piano-playing nephew). The cabinets along the right-hand wall might as well not exist, as far as she is concerned. She doesn't even like to think about, much less look into them, but she let me take a peek. I found what I might easily find at home - boxes stuffed with papers. Only these are also bookplates. Since no one ever really looks at them, no one knows just what might be there. During the course of our conversation the phone kept ringing, and after three or four calls - apparently from the same person - I understood that the collection is on the verge of spilling out into the hallway, for which reason another cabinet has to be arranged. "With a lock!" Frau Doktor Galosy emphasized over and over. "And not a flimsy one like you sent last time. Even I could have put my hand through the door of that one." After that the phone remained sullenly silent. "Where were we?" she asked, and without waiting for my answer, started rattling off facts as though they're part of a stand-up routine. The earliest bookplates, she told me gravely, date from the end of the 15th century, not coincidentally the early days of the printing press and mechanical book production. The plates tended at first to be hand-painted or woodblock prints, though by the beginning of the 17th-century copper engraving had become the preferred method. "The customer," she said, "simply order ed a 'copper. The size of the individual prints differed from what we've grown used to today (as, indeed, did the dimensions of books). Folio-sized ex libris were not uncommon, their decoration most often surprisingly simple - a coat of arms, like as not without a name. The tradition of printing the words "ex libris" on the bookplate won out over time; in the beginning the prints had a more all-around character as identification tags not only for books, but for other movable items as well, such as furniture. "Ex libris" literally means "from the books of thus requiring a name to go along with it and restricting the range of its use. Nearly every language has an equivalent for this term (bookplates, marques de possession, Bucherzeichen), but ex libris is appropriate international usage. The simple coat of arms gave way to more creative designs: portraits, library interiors, and picture puzzles (the scrambled letters of a name, for example). The kind of ex libris that allows you to fill in your own name is nothing new: This cheaper version was available almost from the start. After falling out of fashion toward the middle of the 19th century, the making of bookplates continued stronger than ever just before the turn of our century. (The Eclectic movement and its interest in heraldry, as well as photography and its new possibilities for reproduction, were responsible for the revival.) The '30s marked the last real ex libris craze, when they were collected as exotic rarities like butterflies. They were often used in place of a calling card. Frau Doktor Galosy continued her rapid spiel as though it were a poem she'd learned by heart and now was delivering without punctuation. Occasionally she paused to ask me if I was keeping up, which I said I was. "Good," she'd reply. "Where were we?" A large part of the National Library collection was purchased in the '30s. But another part, she told me, was "created" by an earlier zealous curator who simply ripped pages out of the library's books. She supposed this method would be frowned upon today, but was glad it had been done, just the same. Eventually, Frau Doktor Galosy brought me back downstairs to the main library hall, where I thanked her and we parted. Standing in this gallery, with its several stories of books, I began to think of the nature of libraries - and books themselves - as places of permanence. Places of safety, even, where one puts things of importance: How many times have I come across thoughts scribbled in the margins, photographs, tickets, money, or pressed flowers in books? Ex libris. Why put them there? Because they wil l last. On my way back down the stairway I noticed the name Hadrian on one of the Roman stones. Later, after I had had some time to think, I remembered a passage in Marguerite Yourcenar's "Memoirs of Hadrian": "The written word has taught me to listen to the human voice, much as the great unchanging statues have taught me to appreciate bodily motions. On the other hand, but more slowly, life has thrown light for me on the meaning of books." The human voice is, indeed, the subject of books, and it is to be found not only in what the writer - but also the reader - has left behind.