What a fun book! :-) Or perhaps better said books, as this was originally published as three separate volumes--A Beginner's Manual, Knotwork, and Illuminated Letters. Written and illustrated by Aidan Meehan.
Here is a "step pattern" from the Book of Lindisfarne. The initial grid layout and penciling in took a couple of hours. Next up is the inking in and for that I'll try to pick up a black 0.25 mm Pigma locally. I'll also be poking around the web hoping to find an image of the original manuscript for realistic coloring. Not doing well there...perhaps this step pattern is a little piece on a page? Perhaps I need to extend my library? :-)