Book Stumps Decoders: Design Filter, Please?

Here's a new book about an old book. The new book was designed for a purpose: to try to understand an old book that's a mystery. We know the author of the new book; the author of the old book, the Voynich manuscript, is unknown. Raymond Clemens explores the mystery in The Voynich Manuscript (Yale University Press), examining "a work that has long defied decoders." Reviewing Clemens's book for Nature, Andrew Robinson calls our attention to this "calligraphic conundrum," providing another oppo...