E. Lingle Craig Preservation Lab Blog Preservation and Conservation at Indiana University Bloomington Libraries

homepage for E. Lingle Craig Preservation Lab Blog

You Can’t Judge a Book by the Cover

Part One

You can’t judge an apple by looking at a tree
You can’t judge honey by looking at the bee
You can’t judge a daughter by looking at the mother
You can’t judge a book by looking at the cover.
— Bo Diddley / written by Willie Dixon

Are you looking for reading recommendations?

A group of people sitting in the woods reading books.
Mr. Blatchley reading, against tree, Frank M. Hohenberger Photograph Collection. Courtesy, The Lilly Library, Indiana University, Bloomington, Indiana.

or maybe a Bo Diddley recording?

Bo Diddley singing and playing guitar.
Bo Diddley. Photo by Scott Williams.

If so, you are probably in the wrong place.

On the other hand, if you have books you want to keep for a long time, and perhaps pass on to your children, you may find this useful. Ditto if you work in a research library. Ditto if you’ve ever wondered how books are put together. We are talking here about things that affect a book’s chances of long-term survival.

Portrait of Geoffrey Chaucer on horseback.

For out of old fields, as men say,
Comes all this new corn from year to year;
And out of old books, in good faith,
Comes all this new science that men hear.
— Geoffrey Chaucer, Parlament of Foules

Book conservators know how books are made, and importantly, why and how they fall apart. So I’m going to share some secrets about how to distinguish between a book that is likely to last and one that may not. Hint: As the title of this post suggests, one with a worn cover could very well be a better choice than one that looks good from the outside. In truth, the choice is not usually clear-cut — not by a long stretch. Nevertheless, better choices can be made, and made more easily, when armed with information about the physical aspects of books and how they are put together.

Book conservators work hard to keep books in good condition so that they will be there when you need them. But do you know what has helped the survival of our collective intellectual record more than the collective efforts of book conservators?

Lots. Of. Copies.

Two copies of the same book stacked one on top of the other.
Two copies of the same book.

Any particular book or journal is likely to be found on the shelves of many libraries. Everybody knows that, and that is a good thing. And an individual library very likely has duplicates even within its own collection.

Redundancy is good in the world of information preservation, whether it is physical books or backups of your computer files. When bad things happen to good books — as they do — there will still be other copies.

So why worry about better or worse copies when we have lots of them?

Well, in recent decades the cost of maintaining vast print collections has become a pressing problem for libraries. The space devoted to books diminishes a library’s capacity for other things, such as study space for patrons. When libraries run out of space, difficult choices often have to be made.

Since the 1950s, when post-war prosperity led to increasing rates of collection growth, libraries have used many strategies to cope. Microforms reduced the footprint of voluminous materials such as newspapers. Compact shelving was added. Interlibrary lending meant a library did not have to acquire every book. When those measures were no longer enough, high-density storage facilities were built to house books by size on 30-foot-high shelving. But today many libraries have filled up these facilities too, and financial support for yet more space has been hard to come by.

So what now?

You see where I’m going here. Shedding some of the copies would seem like a reasonable next step, especially older materials, which are no longer used as much as they once were. So this is indeed what many libraries are up to these days — withdrawing some copies, either within their own collections or in collaboration with other libraries.

Samuel Clemens / Mark Twain seated outdoors.

Behold, the fool saith, ‘Put not all thine eggs in the one basket’ – which is but a manner of saying, ‘Scatter your money and your attention ; ‘ but the wise man saith, ‘Put all your eggs in the one basket and – WATCH THAT BASKET.’
– Pudd’nhead Wilson’s Calendar. — Samuel Clemens/Mark Twain.

So then, how does one decide which are the best copies to keep? This is where knowing how books are made comes in.

In Part Two, I’ll get all technical and talk about how you can distinguish between a book that is likely to last and one that may not based on its construction. For now, I will pause and leave you to ponder this illustration. We’ll come back to it.

Diagram of the openability of 4 different binding methods.
From Guide to the ANSI/NISO/LBI Library Binding Standard. Jan Merrill Oldham and Paul Parisi. Illustrations by Gary Frost. 2008

You Can’t Judge a Book by the Cover

Part Two

In Part One I suggested that looks can be deceiving to the untrained eye when it comes to judging which copy of a book has better odds of long-term survival. And I promised to share what book conservators know about how books are made, and how and why they fall apart. So now we are going to look under the hood (the covers, that is).

First, we have to talk about paper.

Way back when, before the Industrial Revolution, paper didn’t grow on trees. It was made out of fibers from cotton and linen clothing and other rags.

Rag collector, 19th century photograph by Eugene Atget.
Lumpensammler (Rag Collector), Paris. Photograph: Eugène Atget

But the increased demand for paper in the nineteenth century led to rag shortages, so in the 1840s papermakers began switching to wood pulp. Unfortunately wood-pulp paper becomes acidic, weak, and brittle over time, whereas older paper made from cotton or linen fibers has remained strong and flexible for centuries. By the 1980s, with the problem now quite evident in library stacks, papermakers began converting to making acid-free paper. But between the 1840s and the 1980s millions of books were produced. And libraries have lots and lots and lots of them.

Book with brittle paper, with pages broken into little bits.
Book with brittle paper, pages have broken off from the binding at the inner margin.

So the condition of the paper is a big factor for long-term survival.

But now you are thinking that books published at the same time are likely to have the same kind of paper, right? And you would be correct. So this doesn’t help a lot by itself when comparing copies. But it is often a combination of factors, including paper strength, that leads to a book’s demise.


An essential thing that makes a book a book is that the pages are joined, or bound, together along one edge in some way. There are numerous ways this can be done. And the way a book is bound often does vary from one copy to the next. The main reason for this is that older books in libraries are likely to have been rebound at some point. And some of the rebinding methods used in the past were, shall we say, better than others. Also, wear and tear often varies from one copy to the next.


A simple but important feature to look for is openability — whether a book lies open on the table by itself, or if you have to hold it open. The way the pages are joined together largely dictates this. Openability is important, not only because those that don’t open well are less convenient to use — although they are — but because a restricted opening is one sign of a binding method that makes future repairs difficult or impossible. (Sometimes the thickness of the paper, or the direction of the paper grain also come into play.)

Two copies of the same book opened on a table. The one at left opens flat, the one at right must be held open.

The openability of the most common binding, or “leaf attachment,” methods found in library collections are illustrated below. Restrictive bindings — those that do not open easily — put stress on the pages. Books that open easily allow the pages to move freely. A book with brittle paper and poor openability is likely to end up broken and sad. And difficult to save. But when a book is bound in a flexible manner, there’s hope, and the chances are better that it can be repaired.

Diagram showing the openability of four different binding methods.

Identifying Leaf Attachment Methods

Below are descriptions of the leaf attachment methods most prevalent in library collections, along with illustrations to help you know what to look for to tell one from another.

Sewing Through the Fold (5c above) is a traditional method of joining the leaves of a book together to form a text block, and has been in use since as early as the 2nd century AD. So it’s kind of time tested.

Sheets of paper (folios) are folded together in groups (called signatures, sections, gatherings, or quires).

Folios and signatures.

and the groups are sewn one to the next with needle and thread.

A book being sewn through the folds.

Sewing through the folds is still the way that lots of books are made. Attaching the pages together through the folds makes a book that opens well, is flexible, and allows for future repairs. There is not a lot of stress on the pages, and that is helpful if and when the paper becomes brittle and weak.

Sewing through the folds can be found in paperbacks as well as hardcovers. Look for even stitches in the center folds and a scallop pattern at the top or bottom edge of the book.

Stitches visible in the folds of a book sewn through the folds.
Close up of two stitches in the inner margin of a book sewn through the fold.
Scallop pattern at the top edge of a text block sewn through the folds.
Sometimes the stitches are hard to find in the centers of the signatures, but you can often see that the book is in signatures by looking at the top or bottom of the book where you can see a scallop pattern.

Adhesive binding (5d) joins single leaves (rather than folded sheets) together with glue and results in good openability, because the pages are attached only by their very, very edges. As long as there are adequate margins, adhesive bindings usually can be rebound.

An adhesive-bound book open on a table.
Adhesive-bound books open well and lay flat on the table.
Adhesive-bound books are single sheets of paper glued together so there are no folds, and no scallop pattern at the top and bottom of the book.

Burst binding is a variation of adhesive binding, but it’s a tricky one. They can be confusing to distinguish from a book sewn through the folds. The top edge has the scalloped edge like a book in signatures sewn through the fold. That is because it is in signatures. It’s just that instead of the signatures being sewn, slots are cut through the folds and adhesive is forced (or burst) through to hold the signatures together. When you look closely at a burst binding you will not see any threads. These usually can be rebound adhesively after cutting off the folds.

Opening of a burst binding.
When you look closely at a burst binding you will not see any threads.
Close up of an opening of a burst binding.
Closeup of a burst binding

Most mass market paperbacks are made with poor-quality adhesives that dry up and cause pages to fall out or the text block to split, as shown below. But if the inner margin is wide enough, these can usually be rebound with a better adhesive, as only a tiny amount of the page edges need to be trimmed away.

A failed adhesive binding broken into sections.
Failed adhesive binding

Double-fan adhesive binding, which uses a high-quality, long-lasting adhesive, is done by commercial library binders and in book conservation labs. The pages are clamped in a press, fanned out, and adhesive is applied. Then the pages are fanned the other way and more adhesive is applied. This deposits adhesive on both sides of the pages (1/16 inch or less). This type of adhesive binding holds up well in most books, but does not work as well on books with thick, stiff pages.

Glue being applied to a double-fan adhesive binding.
Double-fan adhesive binding

Oversewing (5b), the most restrictive leaf attachment method, was used liberally until about 1985 by commercial library binders. Many books that were sewn through the folds originally were rebound later by oversewing, which requires chopping off the folds and some of the inner margin to make a stack of single sheets. Oversewing was also used to bind together the issues that make up journal volumes. Since the mid-1980s, oversewing has largely been replaced by double-fan adhesive binding.

To oversew a book, the folds are chopped off (if present) and a few pages are put into an industrial machine that has a row of threaded needles. The needles and threads pierce through the page edges many, many times. Then another clump of pages is added, and the machine sews through them and interlocks the stitching with the one before.

Exposed spine of an oversewn book.
The spine of an oversewn book showing the thick mass of threads

An oversewn book with flexible paper is probably going to last a long time, but if the paper is brittle, there will be a lot of page breakage, and you may not be able to put Humpty Dumpty together again.

Below is an oversewn book taken apart, page by page, snip by snip with fine scissors and tweezers. There is so much strong thread that it can take hours to take apart one volume. The resulting pages look similar to those torn out of a spiral-bound notebook.

An oversewn book after being taken apart.

Besides the restricted opening, another way to tell that a book is oversewn without taking it apart is to look for the close, irregular stitches in the inner margin. This is often visible in older books as they start to weaken.

Appearance of threads in an oversewn book.
Oversewing stitches look irregular, not evenly spaced

Also, almost all oversewn books have plain buckram cloth covers.

Buckram-covered book.
Oversewn books are almost always in plain buckram cloth covers.

Because oversewn books are made up of single sheets, rather than folded signatures, you won’t see a scallop pattern at the top or bottom as you do with books sewn through the folds.

Hand-oversewn books are less common, but sometimes repairs were done by a kind of oversewing. The most likely hand oversewing you would encounter is at the front of a book (where damage most often occurs first). Hand oversewing is also called whip stitching or overcasting. This type of oversewing restricts opening, but is not as damaging as machine oversewing because the folds are usually retained, there are not nearly as many stitches, and the stitches are much easier to remove.

Whip stitching, or hand oversewing.
Whip stitching, which is sewn by hand, is most likely to be found at the front of a text block.

Side sewing (5a) is another restrictive binding method. It can be sewn by machine or by hand. All the pages are sewn in one long row of even stitches. The stitches can be removed, allowing for rebinding. This can be a bit time consuming, but it can be done.

Machine side sewing.
Machine side sewing

Japanese stab-sewn books are usually made with thin flexible paper and adequate inner margins.

Japanes stab sewing.
Japanese stab sewing is a form of side sewing done by hand

Side stapled books are similarly restricted in opening, but they are usually easier to take apart to repair or rebind. Side sewing and side stapling are usually done on thin books or pamphlets made up of single sheets of paper, but sometimes books made from folded pages have been side sewn or stapled.

Side stapled journal issue.
A side-stapled journal issue.

Pamphlet binding is a single signature of pages sewn together through the fold, often together with a simple cover. Like a book with multiple signatures sewn through the folds, this is a flexible leaf attachment method that can be repaired or rebound very easily. Pamphlets, musical scores, popular journals, ephemera and other short works are often made up of a single signature stapled through the center. Staples can be replaced by sewing to improve durability.

Three and five hole pamphlet sewing pattern.
Three and five-hole pamphlet sewing

So, yes, it’s complicated, but at least now you know – you can’t judge a book by the cover.

For more information on book structures not covered here, see:

University of Illinois. Preservation Self-Assessment Program. Collection ID Guide. Book and Paper, Binding Types

and for an excellent analysis of the many factors involved in withdrawing copies, see:

Considering Sameness of Monographic Holdings in Shared Print Retention Decisions.

2 thoughts on “You Can’t Judge a Book by the Cover”

Leave a Reply to Elise Calvi Cancel reply

Your email address will not be published.