The past is irreversible, but imagination is unlimited. With a twist of fate — and of historical fact — Gallipoli was a military success, Australia had a female prime minister in the 1920s, we won the soccer world cup in 1974, and Gough Whitlam chose his time to retire from the top job.

In Victory on Gallipoli and Other What-ifs of Australian History, prominent historians contemplate how Australia today could have been a very different place but for a decision made or not made, an opportunity taken or not taken. These are the nation's sliding door moments, our alternative history. At the end of each essay, an 'In Fact' section tells the true story to allow the readers to see what has, and hasn't, been changed in the imaginative retelling.

The Cold War had the world teetering on the edge of mutually assured destruction but ended instead with the collapse of the Soviet Union. What if the war had heated up? Peter Stanley writes for the fictional New World Quarterly in 2035, from an Australian Republic still grappling with the complete destruction of Europe and North America, with a psychologically damaged populace and an environmentally devastated world.

What if the 1951 referendum to outlaw the Communist Party had been successful? Would Australia have had its own McCarthy era — harassing sympathisers, inhibiting the trade union movement and banning Communist-inspired literature? Where would be today? Roslyn Russell imagines a book for students replete with case studies on what to do if you suspect your neighbour leans a little too far to the left …

And what if Kingsford Smith had survived his trans-Pacific crossing in 1935? Would he have gone on to further cement his reputation as hero aviator? Or would his personal flaws have undermined his legacy? Michael Molkentin gives us an alternative biography, one in which Kingsford Smith is shunned by this country and ends up aiding a militant Japan's aviation aspirations as the Second World War descends.

With essays by Janette Bomford, Guy Hansen, Carolyn Holbrook, Walter Kudrycz, Michael McKernan, Ross McMullin, Hamish Maxwell-Stewart, John Maynard, Michael Molkentin, Roslyn Russell, Peter Stanley, Craig Wilcox, and Clare Wright.