Isi Leibler (full name Isidore Joseph Leibler), a Belgian-born Australian-Israeli international Jewish activist, was born on October 9, 1934, in Antwerp, Belgium, to Abraham (known as Roman) Leibler and Rachel Leibler, who were involved in the diamond business. Anticipating the rise of Nazism, the family immigrated to Australia in 1939, settling there and establishing roots in the Jewish community. Leibler attended Melbourne High School and emerged as a key advocate for Jewish causes, notably pushing the Australian government under Sir Robert Menzies to raise the plight of Soviet Jews at the UN in 1962, marking Australia as the first nation to do so publicly. A 2021 biography revealed that from 1959, he had operated in Australia as an Israeli intelligence asset while advancing his activism. He served as former Vice President of the World Jewish Congress and held significant leadership roles, including four terms as president of the Executive Council of Australian Jewry from 1978 until his retirement in 1995, as well as involvement with the Claims Conference on Holocaust restitution efforts. Recognized for his contributions, he was appointed Officer of the Order of Australia (AO) and Commander of the Order of the British Empire (CBE). An opinion journalist and political activist, Leibler passed away on April 12, 2021.