Kristie Macrakis uncovers the nearly 3,000-year history of hidden messages
Prisoners, Lovers, and Spies: The Story of Invisible Ink from Herodotus to al-Qaeda
Yale Univ., $27.95
Pig’s bladder, gypsum, fig sap, alum and onion juice — there’s no eye of newt among invisible ink recipes, but blood of dormouse is fair game. By the end of science historian Macrakis’ nearly 3,000-year accounting of secret messages, she’s all but thrown in the kitchen sink (and the cauldron).
If you’re asking whether it’s science or sorcery chronicled in these pages, there’s a chemical explanation for every reaction here. A quick jump to the back of the book reveals a cookbook of secret recipes that once floated spy rings and sunk empires.