Bookbinding Methods: Perfect Binding Uses Glue, Not Thread

Perfect binding holds single leaves together with adhesive along their cut edge. Bookbinding is the work of holding a stack of leaves together at one edge and giving it a cover, often with thread, wire staples, or adhesive. Where the holder grips the paper shapes two things: how far the book opens, and how it breaks.

Look along your own shelf. Open a thin magazine at the middle: staples in the fold are saddle stitching, the method that dictionary describes for “a periodical issue or pamphlet.” In a paperback sewn in sections, thread shows at the center of each section. If neither shows, adhesive is the likely holder.

Where can a binding grip the paper?

A binding can grip paper in three places: through the fold of a folded sheet, through the side of the whole stack, or on the cut edges of single leaves. A 1982 Library of Congress dictionary of bookbinding terms, by Matt Roberts and Don Etherington, splits sewing the same way: through the folds or through the sides. Adhesive adds the third. A section, or signature, is usually one printed sheet folded into a group of pages.

Through the fold: saddle stitching and sewn sections

When a few sheets are folded in half, nested, and stapled through the crease, the result is saddle stitching. The dictionary credits it, and its threaded twin saddle sewing, with full openability right to the gutter, where facing pages meet. Openability is its word for how flat the open leaves lie with no weight on them. The limit is size: how many leaves one fold can take depends largely on paper thickness.

Thicker books use many sections, each sewn through its own fold and linked to the next. Binders in Europe sewed sections onto cords as early as the 8th century, a method the dictionary calls one of the strongest forms of hand sewing known. Coptic binding leaves the links in view, as chain stitches across the spine. In the United States, machine book sewing is nearly synonymous with David McConnell Smyth, who patented sewing machines in 1868 and 1879.

Through the side: strong, but stiff at the gutter

Side sewing and side stitching push thread or staples straight through the whole stack, near the spine. The dictionary calls side sewing “an extremely strong form of sewing” and side stitching “one of the strongest forms of construction.” By the same dictionary, side sewing gives very little openability, and side stitching almost none. Side sewing does better only with a very wide inner margin, very flexible paper, or a very large book.

A side-stitched book has to be designed around this, with wider margins and more flexible paper. Paper logic, the rigid-sheet model this site uses for folded paper, shows why: in it, a leaf can turn only at a crease. A side-sewn book has no crease at its stitch line, so in the model it could not open at all. Real paper bends in the margin past the stitches, and that bend is how each page turns.

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Library binders use a related method: oversewing. It cuts away the folds and sews small stacks of leaves through their edges. It also uses up about 5/16 to 6/16 inch (about 8 to 9.5 mm) of inner margin.

On the cut edge: what “perfect” binding really is

Perfect binding works on single leaves. The dictionary defines adhesive binding as a way of “securing loose leaves” with adhesive instead of sewing, and lists “perfect binding” and “unsewn binding” as other names for it. Some binders fan the clamped leaves so the adhesive reaches a short way onto each one, which the dictionary says forms “a more secure bond.”

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Glue earns its place. The dictionary says adhesive binding generally opens easily and lies flat, costs relatively little over long runs, and suits heavy use over a short life, like a phone directory. Library binders also use it to rebind books on paper that is breaking down. Still, its 1982 verdict was mixed: generally thought inferior to sewing, with permanence “yet to be demonstrated.”

Here the adhesive signs for every leaf on its own. Each leaf is held only along a narrow strip at its cut edge, so that strip does the whole job.

The glue-only book is older than it looks. In 1836 William Hancock patented a rubber version, the caoutchouc binding, which the dictionary calls probably the first adhesive binding. From about 1840, large numbers were made in England and the United States, and at the time they were believed to last. They depended on the rubber staying flexible, and it did not: most caoutchouc bindings have since fallen apart.

Is a hardcover book sewn?

Not necessarily. Case binding is one way to make a hardcover. Its case, the boards and their covering, is made separately and glued on through the pastedowns, the endpaper leaves nearest the boards.

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The dictionary dates case binding to 1820s Britain. Its 1982 entry calls case binding “the principal method employed in both edition and library binding.” Edition binding means binding identical copies in quantity for a publisher.

The case shows how the cover goes on. It says nothing about how the leaves are held: in library binding, they may be oversewn or glued.

How it fails: where each binding gives way

A binding's failures say more about it than its successes do. In a sewn book, the third hand, a name for the hidden holder that keeps a part in place once the hands let go, is the thread's tension. Loose sewing can cause both sewn-book failures below.

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One problem cuts across every method: grain. Machine-made paper has a grain, the direction most of its fibers lie. A well-made book runs it from head to tail, parallel to the spine. Folded the other way, the paper refuses to settle: the fold runs across the fibers, and the leaves are less inclined to lie flat.

Which binding for which job?

Each row below follows the 1982 dictionary, and the CSV gives the dictionary entry behind every value.

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Download the comparison table (CSV) (what the file holds)

Questions readers ask

Is perfect binding bad?

The 1982 verdict on it was mixed. Perfect binding is adhesive binding by another name, and a 1982 Library of Congress bookbinding dictionary says it generally opens easily and lies flat, at low cost over long runs. Its weak points are coated paper, where leftover coating dust can keep the adhesive from gripping well, and permanence, which the dictionary called unproven. Sewing was generally rated higher.

Why won't my book stay open?

Check three things. Side-sewn and side-stitched books barely lie open unless made with wide margins and very flexible paper, because the stitches pin every leaf near the spine. The grain may run across the spine instead of along it. Heavy, thick paper also resists, since how flat a book lies depends on paper weight and thickness, grain direction, and the sewing method.