Despite publicity given to the successes of British and American codebreakers during the Second World War, the study of signals intelligence is still complicated by governmental secrecy over even the most elderly peacetime sigint. This book, first published in 1986, lifts the veil on some of these historical secrets. Christopher Andrew and Keith Neilson cast new light on how Tsarist codebreakers penetrated British code and cypher systems. John Chapman's...