Latest Henry Petroski Book Assesses Evolution and Engineering of Bookshelves

DURHAM, N.C. - After writing six previous books for general audiences on engineering triumphs and disasters, famous bridges, and the histories of the pencil and other interesting objects, the latest volume by Duke University's Henry Petroski focuses on the storing, packaging, displaying and care of books themselves.

Petroski, the chairman of Duke's department of civil and environmental engineering, traces the inspiration for his newest work, "The Book On The Bookshelf" (September 1999, Alfred A. Knopf Inc., New York City), to a reflective evening in his own home study in Durham, N.C.

"As I say in the book, my reading chair in my study faces my bookshelves," Petroski said in an interview. "I usually look up and I see my books, but this one night when I was reading I looked up and I saw the bookshelf itself.

"It caught my attention, and I wondered. I've written about simple things like pencils and paperclips, and they have surprising origins and evolutions. What about the bookshelf.? Is there a story there? Is it more than just a piece of wood between two other pieces of wood?

"It then caught my eye that you could do a lot of engineering analysis on a bookshelf as a bridge of sorts, where the books are like traffic on a bridge. You want it to span a certain distance. You don't want it to bow, deflect or sag.

"I just wondered, is it possible to find out where the bookshelf came from, or is that so simple a question that it's almost meaningless to ask it? I began to root around and found that, actually, there is a really rich history that I was unaware of."

Petroski's fact-packed work begins before there were books bound between covers. Among the other interesting details is information on how the ancients read and kept their form of books: the scroll. Readers learn that scrolls were sometimes stored rolled up in a container not unlike a modern hatbox, or arranged on shelves that resembled a wallpaper storeroom's.

By early in the Christian era, he writes, scrolls began sharing shelf space with the earliest bound manuscripts, which were sheets of papyrus or parchment sewn together in a wood-covered codex - the earliest form of a book as we know it in modern times. Since a big codex occupied more space than a scroll, the shapes and dimensions of bookcases began to evolve.

The codex itself, Petroski writes, evolved from hinged portable writing tables that tax collectors in Roman times could jot on while standing or while sitting on horseback (not good situations to try and work with a scroll). Christians then adopted the codex form of books to distinguish their works from those of Judaism or paganism.

Books were rare and treasured objects, and in the security-conscious Middle Ages medieval monks began locking volumes up between use in chests or wardrobe-like armaria, his book continues. And small studies, called carrels, also evolved in medieval monasteries as places for reading and privacy.

The carrel has survived into modern times. Indeed, Petroski so prizes his carrel at Duke's Perkins Library that he will not reveal its exact location (his book acknowledges that it is on the top floor in the northeast part of the building).

The modern form of the bookcase continued to develop, his book says, as bound volumes began to be kept inside locked rooms instead of book chests. Many of those books had covers decorated with precious stones and metals and protected with a clasp. These features presented sharp edges that could damage other books stored upright next to them. So the decorated books tended to be left face up on tables or lecterns. But those with more ordinary covers were stacked flat like pancakes on a shelf.

As books became more numerous, Petroski describes how demands for space and other considerations led many of them to be stacked upright on the kind of shelves seen today. However, they were initially stacked with their spines facing into the shelf, the reverse of current practice.

The reason for the spine-side-in feature was, again, security. As demand increase, reading rooms - now evolving into what we now call libraries - were no longer locked up from the outside world. Instead, the books were themselves kept chained to the shelves. And it was far easier to attach the chain to a book's cover edge than to its spine.

As is fitting for a civil engineer like Petroski, readers also learn about the changing design considerations - such as light, ventilation and load support - behind the engineering of large library buildings in the days before and after the introduction of artificial illumination.

Petroski's book is illustrated with a number of old paintings and woodcuts, which he uses as windows into the past. "It's very difficult, if not impossible, to find somebody writing about exactly how books were arranged on bookshelves in the 14th or 15th century," the author said. "But people were painting them. And by looking at paintings you can at least infer, especially if you look at painting after painting and see the same pattern over and over again."

There are also plenty of architectural drawings and photographs of libraries, some of which he visited himself. He recalled spending time in one rare book collection at the University of Iowa library "where they gave me some white gloves and turned me loose," Petroski said.

"Some of the books were from the 16th Century, and they still had clasps on them that worked. I don't like to just draw upon reading. I like to physically check that things are a certain way. It's always important to go back to the artifact."

Petroski said he was especially struck as he did his research "that chaining books was so extensive in the Middle Ages in monasteries. I didn't realize how widespread the practice was. I didn't realize that whole libraries were chained.

"And the consequence of that chaining was that books were first shelved on lecterns, and then when they began to be shelved vertically they were shelved with their spines inward. That fascinated me. It provides a lot of insight into how technological systems evolve.

"Many people in the 20th century might say, 'Well, how else would you show books but spine outward. It's the only logical way.' But that's clearly not true when you look at the historical development of the book and the bookshelf."

Petroski, Aleksandar S. Vesic professor of civil engineering and a professor of history at Duke, is a member of the National Academy of Engineering.

His previous works include "To Engineer is Human" (1985, St. Martin's Press), "The Pencil" (1990, Knopf), "The Evolution of Useful Things (1992, Knopf), "Engineers of Dreams" (1995, Knopf), "Invention by Design" (1996, Harvard University Press) and "Remaking the World" (1997, Knopf).