For nearly fifty years, Arthur Calwell's political legacy has been overlooked. As a Labor federal member, Minister for Immigration, and Opposition leader, he shaped Australia's multicultural identity post-WWII. Serving under notable Labor leaders, Calwell navigated party splits and nearly unseated PM Menzies in 1961, revitalizing Labor's confidence and national policy. This monograph by Professor James Franklin and Gerry O'Nolan not only revisits Calwell's political journey but also delves into his deeply influential Catholic beliefs, distinct in an era where religion had a prominent role in public and personal life.