Letterlocking : The Hidden History of the Letter

Letterlocking: The hidden history of the letter by Jana Dambrogio and Daniel Starza Smith, with the Unlocking History Research Group, uncovers the largely forgotten practice of "letterlocking": folding, slitting, and securing a letter so that it becomes its own envelope, a technique used across cultures for centuries before the gummed envelope arrived in the 1830s.

Drawing on research into more than a quarter of a million historical letters, the authors trace how everyone from Elizabeth I to Japanese samurai lords used these ingenious folding methods to protect the privacy of their correspondence, and how the physical folds themselves can reveal information about a letter's sender, security, and secrets.

Richly illustrated with over 500 diagrams, the book includes a dictionary of letterlocking terms, step-by-step instructions for recreating historical folds at different skill levels, and methods for analysing locked letters, making it both a work of scholarship and a hands-on guide.