Think invisible ink is kids’ stuff? Science historian Kristie Macrakis’ new book Prisoners, Lovers, & Spies: The Story of Invisible Ink from Herodotus to al-Qaeda
tells a different tale. Macrakis argues that for prisoners, lovers, and spies throughout history, communicating secretly was a matter of life and death. She reveals the secrets of invisible writing, from the simple (lemon juice) to the complex (microdots).
For more information about Kristie Macrakis' "Egg Challenge" click here
And for a recipe for invisible ink using starch, read an excerpt from the book