A cryptology instruction book… 202 years old.

http://www.thebeerbarrel.net/showthread.php?8091-NSA-Declassifies-200-Year-Old-Book

Included in this new motherlode (.pdf) of supposedly secret-packed documents: a 1944 report on Japanese merchant ships, a 1946 dossier on Chinese railroads, and a 1954 German article on Lenin’s use of secret writing (with milk) while in prison. Presumably, this refers to Lenin’s stint in Siberia, in the mid-1890s. Exactly why Vladimir Ilyich’s reliance on lactose letters needed to be kept under wraps for 11 decades, the NSA doesn’t say.