Hundreds of years ago, people developed ingenious methods to secure their letters from prying eyes – and they did it with only paper, adhesive and folds. Late at night on 8 February 1587, an ...

Over recent years we’ve been treated to a series of fascinating advances in the world of x-ray imaging, as researchers have developed their x-ray microtomography techniques and equipment to the point ...

Abstract: In this section we will take a close look at twelve historical letters, written on paper from the 1580s to the 1970s, that demonstrate some distinctive features or techniques of ...

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 ...

An Unlocking History Research Group team member holds a rare unopened example of a letterpacket with a paper lock. (Unlocking History Research Group) Hundreds of years ago, before the invention of ...

On the eve of her execution in 1587, Mary, Queen of Scots wrote what is thought to be her very last letter. She had been imprisoned for nearly 20 years for the perceived threat she represented to ...

Communication through written word existed long before the days of text messages and DMs, and even then some kind of security was needed to protect people’s secrets. When we think of a handwritten ...

The researchers virtually opened the letters with an advanced X-ray machine. They then used computers to analyze the folds and create a readable, digital model of the unfolded message. Unlocking ...

In 1697 a legal professional in the French city of Lille wrote to his cousin in the Netherlands to request a relative’s death certificate, possibly in order to finalize an inheritance. He folded and ...

Keys: How to Use this Book -- Introduction to Letterlocking -- Building the Story of Letterlocking -- Reading Letterlocking Features -- Locking Mechanisms, Security, and Authentication -- Distinctive ...