In December 1944 General Blamey, the commander-in-chief of the Australian Military Forces, was handed a file. It contained decrypted radio intercepts which proved that the Imperial Japanese Army was receiving top secret information - US and Australian war plans. Material that could lead to the death of Allied servicemen in the Pacific. The most likely Canberra. So began a hunt that took five years, involved the world's most secret intelligence organisations and resulted in the exposure and neutralisation of a Soviet espionage network in Australia. Breaking the Codes is a story of international counter-espionage and signals intelligence. It tells of a secret war which sowed the seeds of suspicion in Moscow, Washington and London, seeds which flowered in the Cold War and led to the creation of ASIO.