The Book Doctor Is In: Bookbinding 101

book doctorAlright, it’s time to start dealing with more difficult repairs. In my live workshops I always started by reviewing the various types of book bindings and the names of the many parts that make up books to be sure everyone understood what we were dealing with. Even in a blog post, I think a bit of book learnin’ still makes sense.

2 Common Types of Book Bindings

I. Hard Cover Books

While you will encounter many methods of binding, the two most common types of modern books are hard cover and paperback. Hard cover books have rigid covers and are stitched into the spine. Looking at the top of the spine, the book consists of a number of signatures (groupings of pages) bound together. When the book is opened in the middle of a signature, the binding threads are visible. The signatures are sewn together at the spine to form a text block. In the past several years it has become common to use an adhesive to assemble the signatures rather than sewing them. Glued books appear similar to those with sewn bindings but are usually not as durable. You will generally use the same materials and techniques for in-house repairs to both sewn and glued hard cover books. A second common method for assembling hard cover books is referred to as “Perfect binding.” In this system, each page is a separate sheet and all are glued together at the spine. Individual signatures are not seen if the book is viewed at the top of the spine. In general Perfect bound books are not as durable as books assembled using either sewn or glued signatures.

II. Paperback Books

In mass market paperbacks, each page is an individual sheet and is glued into the paper cover at the spine. Since they are assembled using hot glues which will dry and become brittle, paperback books will lose pages or come apart completely over time. Reassembling them with a good liquid plastic adhesive such as Norbond™ will prolong the life of your paperbacks considerably.

Parts of a Book

Now that we’re getting into more extensive repairs, we’ll be using terms to describe the various parts of hardbound books that may be new to you. This illustration will be helpful in creating a common language and understanding of each part of a book and how they interrelate. You’re most likely familiar with some of the terms shown in the illustration below, but I bet there will be a few new ones for you. The most important are described below:


Notice in the illustration on the far left that the arrow pointing to the top area of the book is labeled “Tube.” The tube is the gap in the spine area between the cover and the text block of most hardbound books. It’s what allows you to open a book without placing strain on the binding. If the book was originally assembled with a tube, it’s imperative that you DO NOT do anything during repairs that damages the tube or causes it to stick together. All that said, many poorly-bound books are not assembled with a tube in the first place and the text block will often tear away from the cover in normal use.  Sadly, this means you’ll be making a lot of repairs because of this deficiency.


In books that are sewn together and in many that are glued, pages are gathered into groups called signatures. Multiple signatures are then sewn or glued together to form the text block.


The super is what holds the text block and cover together. It is usually a cheesecloth-like fabric but is often made of paper in cheaply-made books. The text block is glued to the super and the super is wider than the text block. The “wings” on either side are glued to the inside of the cover.

Paper Lining (outside of the super)

This lining is applied to books with a cloth super so that the adhesive used to glue the super to the text block does not stick the tube closed.


The hinges are located where the rigid front and back cover boards meet the spine of the cover. Since the hinges must be flexible in order for the book to open, they are usually not well reinforced and are the weakest area of a book’s binding.

Repairing Loose Hinges: Early Stage

In its early stages, a loose hinge will seem like a minor problem that can be ignored. This is always a bad assumption as a loose hinge is an early warning sign of serious problems that can develop in the near future. As shown in the first illustration below, a loose hinge is present as the text block begins to tear away from the inside of the cover. If corrected early, this is a simple repair. If allowed to continue, much more extensive repairs will be needed.

A loose hinge is the first sign of trouble for book binding.
Use a mending stick dipped in Demco® Norbond™ Adhesive

To repair a loose hinge simply use a mending stick to apply Norbond Liquid Plastic Adhesive to the area where the side wing of the super and the end papers are tearing away from the cover boards. Take care not to allow the adhesive to get into the tube as this will cause it to stick closed and place strain on the binding when the book is opened. When you have an even coat of adhesive over the area that has torn loose, smooth it with a plastic folder and simply close the book. Next, place a light weight on the cover and let the repair dry overnight. This repair is shown in step-by-step detail in the Book Repair Video below.

Repairing Loose Hinges: Advanced Stages

If a loose hinge has gone untreated for some time, you may notice that the end papers over the super in the hinge are tearing or that the super itself is starting to tear. If so, this tearing can usually be repaired by using Demco Paper Hinge Tape or Adhesive-backed Binder Tape which is attached over the damaged hinge using Norbond.

Demco also has 3 types of pressure-sensitive hinge tapes which eliminate the need to give liquid adhesive time to dry. These tapes are: Easy Bind Tyvek Hinge Tape, Vinyl Hinge Tape and Tyvek Hinge Tape with Liner. When time allows though, I prefer working with the liquid adhesive as I am able to slip the tape exactly where I want it. This repair is also shown in the Book Repair Video.

Next up: Rebuilding Broken Books

Our next post will detail how to reassemble hardbound books that have come apart. As always, feel free to use the link below to post any comments or questions and I’ll respond. I may use your input in future posts! Throughout this series, we’ll be referring to two resources from Demco. The pamphlet Demco Collection Care Guide and the Demco Collection Care DVD are both available to help you through your book repair challenges.


John Ison

John Ison

John Ison retired in 2011 after working with Demco for more than 25 years, most recently as the Director of Library Relations. During that time he conducted over 300 book repair workshops, wrote the Demco Collection Care Guide, and wrote and produced the Demco Collection Care DVD.