You are here

Mathematical Treasure: Abraham Lincoln's Cipher Book

Author(s): 
Frank J. Swetz (The Pennsylvania State University)

Abraham Lincoln (1809–1865), the 16th president of the United States of America, came from a rural background. It was long believed that he was self-educated and received little formal schooling; however, some emerging documents point to the fact that, indeed, Lincoln did have a formal education. Pages of a cipher book belonging to Abraham Lincoln have been discovered in various library collections, including Columbia University, Harvard University, and the Lilly Library of Indiana University. Here are two pages of this book concerning the computation of simple interest.

It is thought that the book can be dated to the period between 1820 and 1826, when Lincoln was an adolescent. The book was given by Lincoln’s stepmother to his former law partner, William Herndon, who, when Lincoln became well known, distributed them as presents to various friends.

Nerida Ellerton and Ken Clements examined all of the known extant leaves in Abraham Lincoln's Cyphering Book and Ten Other Extraordinary Cyphering Books (Springer, 2014).

These images are presented through the courtesy of the Lilly Library, Indiana University, Bloomington, Indiana.

Index to Mathematical Treasures

Frank J. Swetz (The Pennsylvania State University), "Mathematical Treasure: Abraham Lincoln's Cipher Book," Convergence (August 2019)

Dummy View - NOT TO BE DELETED