Most poisonous book

The most poisonous book ever published is Shadows from the Wall of Death, a folio volume compiled by American physician Robert Kedzie and published by W.S George & Co. of Lansing, Michigan, in 1874. The book was written to warn the public about the dangers of the arsenic-based dyes used by some contemporary wallpaper manufacturers, and included 86 leaves of wallpaper (each measuring 23 x 48 cm) that the author had identified as particularly dangerous. Combined, these leaves contained as much as 36 grams of arsenic.

The levels of arsenic in the paper Kedzie tested during his research varied from 0.3 - 3.8 grams of arsenic per square metre. This means that the wallpaper for a 5.5 x 3.7 m room could have contained as much as 167 grams of arsenic. As little as 1 gram of arsenic, if ingested, can be fatal to a healthy adult, and regular exposure, even to tiny quantities of the substance, can cause severe chronic health issues.

In Dr Kedzie's introduction, he mentions a case of a 9-year-old girl who suffered from multiple chronic health issues. When the wallpaper of her bedroom was analysed, it was found to contain 3.4 grams of arsenic per square metre, and that much of the original pigment was found to have flaked away as a fine dust.

Only four copies of the book's original print run of 100 survive, and each has been either had its pages sealed in plastic or is stored in an air-tight container.

The popularity of arsenic-based dyes in the 19th century, means that several libraries have discovered toxic tomes in their collections. However, in other cases the poisonous paper is restricted to decorative covers added by Victorian bookbinders. In 2018, for example, researchers at the University of Southern Denmark discovered a set of renaissance manuscripts that had been bound with arsenic green covers in the mid-19th century.