Most non-Indigenous Australians know of Charles Perkins. Many are familiar with a few other Aboriginal leaders. Yet few have heard of William Cooper, one of the most important Aboriginal leaders in Australia's history. "Thinking Black" tells the story of Cooper and the Australian Aborigines' League, and their campaign for Aboriginal people's rights. Through petitions to government, letters to other campaigners and organisations, and entreaties to friends and well-wishers, the book reveals their passionate struggle against dispossession and displacement, the denial of rights, and their fight to be citizens in their own country. Bain Attwood and Andrew Markus document the circumstances behind the most significant moments in Cooper's political career -- his famous 1933 petition to King George V, his call for a 'Day of Mourning' in 1938, the walk-off from Cummeragunja in 1939 and his opposition to an Aboriginal regiment in 1939. It explores the principles Cooper drew on in his campaigning, not least his 'Letter from an Educated Black', surely one of the most intriguing political testaments by an Australian leader. "Thinking Black" sheds new light on the history of what it has meant to be Aboriginal in modern Australia. It reveals the rich and varied cultural traditions, both Aboriginal and British, religious and secular, that have informed Aboriginal people's battle for justice, and their vision of equality in Australia of two peoples: equal yet distinct.