Off the Normandy beaches on D-Day floated three secret command ships nobody talks about. Converted into floating intelligence hubs bristling with radar and hidden radio rooms, the Fighter Direction Tenders FDT13, FDT216 and FDT217 became the Allies' eyes and ears above the invasion fleet — intercepting German wireless traffic in real time, directing waves of Spitfires overhead, and helping down an estimated 76 Luftwaffe aircraft while losing only one ship to enemy bombing. Th

Celebrate NSIST's 2nd birthday

To help those interested in Second World War UK cryptology who wonder about the difference between an indicator and a discriminant, what forty-weepy might be, or what bonking and blogging meant at that time, Tony Comer has compiled from original sources a glossary. It’s available at https://www.nsist.org/glossary and, as part of NSIST’s educational remit, is completely free to access and use. It is the start of what we hope will develop into an online reference library. Pleas