Popularly known today as Z Special Unit, or by the wartime cover names of Inter-Allied Services Department (ISD) and Services Reconnaissance Department (SRD), Special Operations Australia (SOA) was the Special Operations component of the US-led Allied Intelligence Bureau in the Pacific Theatre during the Second World War. From the secret files of Z Special Unit, and the third in a set of five volumes, Volume 3 - Communications describes the communications links and equipment which were the lifeline for "Z" Operatives in the field. From "Z's" early days relying on Dutch military communications stations in Melbourne and Darwin to the establishment of dedicated "Z" communications stations in Darwin, Morotai and Labuan, Vol 3 provides the only comprehensive history of these sites ever committed to paper. Radio and Special Forces enthusiasts will be agog at the appendices in this volume, which not only include copies of the actual operating instructions and technical manuals for much of the specialist SOE communications hardware used by "Z" during the war, but also the once-top secret SOE ciphers and codes used by Z parties in the field. The Official History of Special Operations Australia, Volume 3 - Communications is a unique record of one of the most important aspects of Second World War Special Operations.