The quest for justice has seldom been more grippingly documented than in the book This House of Grief. The Australian novelist, essayist, screenwriter and journalist Helen Garner witnessed the trial of Robert Farquharson, charged with murdering his three children by drowning. This is not her first attempt to grapple with complex issues of justice and truth – Joe Cinque’s Consolation and The First Stone canvas equally disturbing territory. The much-awarded, sometimes controversial, Garner talks to Mary Peters.