Letterlocking

The Hidden History of the Letter

Jana Dambrogio & Daniel Starza Smith

with the Unlocking History Research Group

Publisher: The MIT Press

Publication date: March 4, 2025.

$40.00

Hardcover | ISBN: 9780262049276 

528 pp., 9 x 9 in, 361 color illus.

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Description

The rich history of a centuries-old document security technology—folding and securing a letter into its own envelope for delivery—and a comprehensive guide to learning how to make your own locked letters.

Before the invention of the gummed envelope in the 1830s, how did people secure their private letters? The answer is letterlocking—the ingenious process of folding, slitting, and securing a letter with a strip of paper and sealing wax so that it becomes its own envelope. The practice, used by historical figures ranging from Elizabeth I and her spymaster to Japanese samurai lords, and nearly entirely forgotten, was an everyday activity for centuries, across cultures, borders, and social classes. In Letterlocking, Jana Dambrogio and Daniel Starza Smith, experts who have pioneered the field over the last ten years, tell the fascinating story of letterlocking within epistolary history, drawing on real historical examples from all over the world.

Fully illustrated with more than 500 images and diagrams, including a dictionary of hundreds of technical terms and concepts, Letterlocking describes the essential precepts of the practice and provides sources of practical support needed for beginner and advanced users of letterlocking. The authors also advocate for the understanding of letterlocking and for its inclusion in a range of intellectual and cultural enquiries, from conservation science and archival databases to historical television shows. By the end of the book, readers will learn how to make locked letters, study letters that may have been locked, and categorize those letters using systems the authors developed while studying over 250,000 historic letters.

Letterlocking will be accompanied by a website, freely accessible scholarly articles, and instructional videos and diagrams, as well as foldable, tear-out sheets with instructions on how to fold and lock a letter.

Authors

Jana Dambrogio is the founding director of the Unlocking History Research Group. She previously held positions at Massachusetts Institute of Technology, the US National Archives, the United Nations, and the Vatican Apostolic Archives.

Daniel Starza Smith is Senior Lecturer in Early Modern English Literature at King's College London.

In 2015, Dambrogio and Smith co-founded the Unlocking History research group (letterlocking.org), an international and interdisciplinary collection of experts dedicated to studying historical communication technologies.

Updates added: 28 August 2026