What's It About?

I get asked: what's your book's title, and what's it about?

The working title is: Expositor. The project investigates the world's oldest information visualization, a 3-metre tree diagram drawn up in the Roman Empire. This chart in Latin which sets out biblical genealogies from Adam to Jesus, intertwined with threads of Jewish political history, has been hidden in plain sight for centuries and has never been examined at book length before.

The original chart is now lost, but medieval copies allow us to reconstruct how this diagram might have looked. Its historic title is unknown, so it is nowadays code-named the "Great Stemma" (GS). You can see a provisional reconstruction of it online on my website, which serves as a long-term data-dump for my research (and is not especially easy to read).

The book will a good read. Using a narrative in the style of a documentary film, Expositor meets with investigators, proceeds from clue to clue, skirts dead ends, and climaxes at a solution which reveals  the origin of the GS. As the story unfolds, it emerges that the chart is five centuries older than previously thought, probably drawn with disciplined skill and careful design in about 420 AD.

Expositor will propose that the GS was inspired not by maps or geometry, but by board games and the abacus, and relates how it was the progenitor of a 16th-century craze for genealogy as well as a remarkable Chinese chart, along with all our modern trees, timelines and mind-maps. The book culminates in a discussion of what it means to visualize information.

The Roman-era chart effectively invented a new technology, leading up to the graphic user interface used in every touch-screen today. I argue that diagrams and visual displays exploit the computing power of human vision to short-cut reasoning tasks. Cognitive science is only now able to grasp what a major shift in human culture this was. My research places that shift in the ancient world.