Few can fail to be moved by the horrendous scenes of September 1922 on Smyrna's quay, where hundreds of thousands of Greek and Armenian refugees crowded into a hellish environment. Many starved within the stinking, frantic crowds and were beaten, raped and randomly killed by the Turkish army. Then there were those who chose drowning over burning by the flames that consumed the city.

Papoutsy is particularly good at unravelling the myths from the solid evidence, and he is keen to show that the Allied ships that crowded the harbour were not all indifferent to the plight of the Greeks who were desperate to flee. The unlikely and almost entirely unsung hero of the exodus was a short, bespectacled New Yorker with tubercular lungs who worked as Smyrna's YMCA secretary. Seeing the imminent disaster unfolding before him, Asa Jennings approached various ships and eventually persuaded an Italian captain to take 2,000 refugees to nearby Mytilene. From there he not only set up relief committees, but asked the dithering Greek government to put all ships in the Aegean at his disposal.

This daring "everyman" succeeded, becoming a de facto admiral of the Greek navy. Making sure that Greek ships were accompanied in and out of Smyrna's harbour, "Admiral" (as he was subsequently nicknamed by fellow Americans) managed to save about 300,000 mostly Greek refugees before the Turkish deadline at the end of the month. Although Jennings was honoured with Greek decorations for his heroism, he died 10 years later and was quickly forgotten. He is not mentioned in any Greek museums and only in a few books.

Huge numbers of Greek men were separated from their families in Smyrna and were never seen again. But Greece absorbed over a million people into its existing population of five million - an extraordinary achievement, which brought revitalisation and energy along with the countless personal tragedies.

Jennings was not the only hero to come from American ranks. Papoutsy names the philanthropic organisation Near East Relief, which had been in the region since 1915. Dr. Mabel Elliott was among those who walked and rode on donkeys through hundreds of kilometres of inland Turkey to save Greek orphans.

Papoutsy is no professional historian, but the reader gets the sense of uncovering the story along with the author, whose enthusiasm for his subject is palpable. There are numerous photographs, copies of telegrams, ship log books, official documents and witness statements ­all a testament to his tenacious research.

Smyrna's destruction in 1922 is part of a controversial and complex series of events that still haunts descendents of those who fled. This book tells the well-known story but from a new perspective. And above all it shows how one "insignificant" person can rise to an extraordinary challenge and change history.

Ships of Mercy: The True Story of the Rescue of the Greeks, Smyrna, September 1922 by Christos Papoutsy is available from www.amazon.com

* Sojka Zinovieff is the author of Eurydice Street: A Place in Athens and Red Princess: A Revolutionary Life