Bookbinding 101: Linen Tape
When a book structure calls for tape, linen tape was traditionally used, and today it is still used by most bookbinders and conservationists instead of cotton tape.
It's not sticky backed tape like duct or masking, rather, it is basically a narrowish woven fabric, which you sew, and maybe also glue, to the pages when constructing some styles of books. The ends of the tapes are then glued, and/or sewn, onto the covers. The last photo below shows one way tape is used in bookbinding (however ribbon was used rather than linen tape—the stitch is the Romanesque stitch).
Linen tape comes in different sizes. Just pick the width that fits your design and/or budget.
Cotton tape is not as strong but it is cheaper, so if you're making a book that doesn't need to last for a long, long time, then it can be a good alternative that costs less.
Three reasons to try substituting linen book cloth for linen tapes
Reason 1: You can cut the book cloth into strips as wide as you need to, which especially helps when creating larger books.
Reason 2: If backed with paper, linen bookcloth adds extra strength to the binding, and adds a little thickness (which can help for reason 3).
Reason 3: You can make fun designs with the tapes on the inside or outside of the cover by cutting the ends into shapes. You may optionally place the decorative ends of the tapes on the face of your cover, and depending on the book structure it may either show as a raised design through the cover material, or you may leave it visible. The last photo below shows visible tape on a completed book (albeit with ribbon instead of book cloth).
You may of course use traditional linen or cotton tape in similarly decorative ways, but book cloth gives more options in width, shape, and color.
You can also use ribbon instead of tape or book cloth, but durability may not approach that of linen.