James Scullin, early school leaver, jack-of-all-trades turned grocer, journalist, union organiser and politician, pious and devout Catholic, is more of a puzzle than might be expected.

Sworn in as prime minister in the week of the Wall Street Crash, in October 1929, he was bewildered and politically devoured by the economic and sociopolitical turmoil of the Great Depression. In Scullin's defence, no world leader shone brilliantly in the immediacy that followed the emergence of the Great Depression, its consequent economic decay, and massive, rising unemployment.

Australia's first Prime Minister of Catholic faith, which profoundly influenced him, though he saw secular and religious principles as compatible rather than competing, Scullin faced many policy and political challenges. Besides the Great Depression, there was Labor Party factionalism and betrayal, and the need to deal with strong and difficult personalities. Amid all those unrelenting pressures, Scullin's intrinsic decency, sincerity, and humility stood out.

There is much to admire. He profoundly influenced and helped to shape the achievements of the Curtin and Chifley governments.

Never an insider or at ease with the trappings of high office; Scullin was more of an outsider close to power. He demanded of government large things, seeing the enemy as those showing indifference and apathy in the face of injustice. Erected over his grave a tall granite Celtic cross stands. Emblazoned on the stonework are Scullin's words: "Justice and Humanity demand interference whenever the weak are being crushed by the strong." Those words, as this monography crisply explains, explain his life's work.

Michael Easson AM is a businessman, company director, former union leader and Labor historian. Thirty years ago, he was Secretary of the Labor Council of NSW [now called Unions NSW], a Vice President of the Australian Council of Trade Unions; and Senior Vice President of the NSW ALP. He published Connor Court's Whitlam's Foreign Policy as well as In Search of John Christian Watson. Labor's First Prime Minister.