As you climbed the rickety stairs of an old woolshed at Sydney harbor in 1944, you could hear rows of men and women in uniforms and headsets tapping away vigorously at small machines, under the careful watch of their young female trainers. Presiding over the cacophony was a tiny woman, known to everyone as "Mrs Mac," one of Australia's wartime legends. A smart girl from a poor mining town, Violet McKenzie became an electrical engineer, a pioneer of radio, and a businesswoman. As the clouds of war gathered in the 1930s, she trained young women in Morse code, foreseeing that their services would soon be needed. She was instrumental in getting Australian women into the armed forces. Mrs Mac was adored by the thousands of young women and men she trained, and she came to be respected by the defense forces and the public too for her vision and contribution to the war effort. David Dufty brings her story to life in this heartwarming and captivating biography.