August last year, I submitted a site review on the famous Russian Fialka cipher machine. This beautiful piece of Cold War technology, introduced in 1965, was top secret until the 90's. Recently, Paul Reuvers from XAT in the Netherlands has composed a magnificent detailed description on the Fialka.
His web pages includes many detailed drawings, wiring diagrams and a manual to the Fialka. In his manual, you'll find the history on Fialka and a very complete technical description. A must for crypto geeks! He also published two very nice Fialka simulation programs, for both Fialka M125-xx and M125-3xx, written by Chernov. All information can be found on Paul's Fialka pages. Some time ago, Paul also wrote a beautiful Enigma Cipher Machine simulator for RISC OS, and created an electronic DIY building Kit, the Enigma-E, which is fully compatible with the real German Enigma. Great stuff!