When I began to get the idea of designing a volume of patterns myself I had to wonder why on Earth one more book ought to exist. It didn't seem to be enough to offer a series of designs that were original and unique, although these are; the fields simply too wide for that alone to matter. I think I found the answer when I thought about what all those books were, and how they address what an artist needs and wants.
As I see it, books of Celtic knotwork designs fall into two types.
The first type, like George Bain's venerable Celtic Art: the Methods of Construction, is a collection of traditional patterns that have been deconstructed into a system that the artist can use to recreate them by plotting them on a grid, on a series of dots, or with some other device that may or may not be similar to methods used by scribes and artists during the Middle Ages. Books like these are valuable tools for anyone who wants to understand how the patterns work, and wants to either build them up from scratch or understand how new patterns can be created.
The second type of Celtic knotwork reference is nothing more than a clip art collection - often line drawings based on period art, sometimes reprints of work that's fallen into the public domain. These designs can include repeating borders, but those are most often presented as complete borders that you're expected to copy as they are. This offers very little control over the size or shape of the border itself.
Each of those two books addresses a need. But neither one corresponds, exactly, to the way I work myself.
As I kept thinking about what a book like this one might be good for, I tried to come up with a presentation for the designs that would work, as much as possible, the way I do.