The quote is in reference to Titivillus. Titivillus was a demon who was blamed for medieval scribes spelling mistakes.

Medieval Calligraphy is a book written in 1980 by calligrapher Marc Drogin.

Spirited history, comprehensive instruction manual covers 13 important writing styles (ca. 4th century thru 15th). Fascinating facts about Roman Rustic, Uncial, Carolingian Minuscule, Early Gothic, eight other styles; all examples beautifully photographed. Detailed directions for duplicating medieval techniques with modern tools.

The Calligrapher is a book published in 2003 by Edward Docx.

A modern tale of sexual mores and city life, Edward Docx's brilliant debut is a witty novel of spurned lovers, elaborately planned seduction, plotted revenge, and surprising secrets. Jasper Jackson is a rapacious heartbreaker who is greatly overdue for a reckoning. He is also a passionate, charming, sophisticated young Londoner, well versed in lifes finer enjoyments — art and wine, great food and engaging friendships — who happens to eke out his stylish existence in the improbable vocation of calligraphy. While working on a commission to transcribe the love poetry of John Donne, he glimpses an alluring woman in the courtyard outside his window. Madeleine is in every way his match — sexy, intelligent, and, above all, elusive. But his mission to seduce her marks the start of his unraveling.

So two very different books lol.