Letterpress Copying Books

Letterpress Copying Books made use of what is known as the “Letter Copying Book Process.” A letter copied using this method needed to be written with a special ink. It was then pressed onto a moist sheet of paper and a portion of the ink was transferred to the paper, producing an image of the original. Originally hand pressure was used to facilitate the transfer, but eventually the pressure was applied by using rollers, and finally presses. The process dates back to 1655, was further refined by James Watt in 1750, and at the beginning of the nineteenth century, reached the form that came to be used as a way to copy letters in Mary Baker Eddy’s household. While better methods of copying documents continued to be developed, the Letter Copying Book Process was in use to some extent until the 1950s.

In Eddy’s time, it was usual to purchase “Letterpress Copying Books.” These were bound volumes consisting of up to 1,000 numbered pages of letter-sized blank tissue paper. Eddy or her secretary could write a letter and retain a copy by moistening a page in the letterpress book, pressing the original letter against the page and applying pressure by means of a press. The Library’s collection of Mary Baker Eddy’s papers includes a number of these letterpress books. In cases where original letters sent out by Eddy no longer survive, the copies in the letterpress books have become invaluable in preserving the information they contained.