"It was an experience writing a book where I was able to speak to the vets who were there and ask them questions," Mr Cameron said.

"Normally I'm writing about things that happened 100 years ago and you don't get the chance to speak with anyone then."

Mr Cameron said that even 50 years on, the memories of the veterans remain very vivid.

"One vet I spoke to said, 'I'm glad we're speaking about this but I know I'm going to have nightmares for the next few days'.

"I said to him, 'Do you want to go on?', and he said, 'Yes, I want to talk'."

On the afternoon of August 18, 1966, in a rubber plantation in Vietnam, 108 Australian and New Zealand troops from Delta Company of the 6th Battalion of the Royal Australian Regiment faced a force of about 2000 enemy Vietnamese Main Force Soldiers and Vietcong guerillas.

Cameron's book is subtitled Australia's Four Hours of Hell in Vietnam and for the next four hours that's what the troops faced. Outnumbered 20-1, and under intense enemy fire, D Company fought off wave after wave of enemy assaults in monsoonal conditions. RAAF helicopters dropped boxes of ammunition to resupply the troops as the firefight continued but as the evening went on the situation grew even more dire. And then about 7pm, when all seemed lost, the relief company of infantry, in armoured personnel carriers, arrived and drove off the enemy.

But the cost was high. Seventeen Australian soldiers were killed and 25 were wounded, one of whom died nine days later. One third of the company was dead. Official reports put VC deaths at 245 but some say up to 800 were killed and as many as 1000 wounded.

For the casualty rates alone, says Cameron, Long Tan will be remembered as one of the critical battles of the Vietnam war.

But while conducting his research he found that many of the veterans were more affected by the aftermath, from having to return to the plantation in the days after to recover and bury the dead.

"When the commander of D Company, Major Harry Smith, told the men they were going back in they didn't appreciate it," Cameron said.

"They didn't know if the Vietcong had cleared out, they wanted to go to Long Tau for some R&R."

Cameron says Smith saw the importance of gaining psychological control over the battlefield, of recovering the bodies.

"By all accounts now he made the right decision and all the men I spoke to agreed that it was the right thing to do."

Cameron realises it was only through speaking to the veterans that he was able to gain this insight. With a PhD in biological anthropology from the Australian National University and years of fieldwork, Cameron says he would like to do more books where he can talk to people about what happened.

He hopes that wars in the Middle East and Afghanistan receive the same treatment from military historians.

"We need to honour these people by telling their stories, by allowing them to tell their stories. We need to understand what people have gone through and document as much as we can."

The Battle of Long Tan: Australia's four hours of hell in Vietnam, by David W. Cameron. Viking. $35.

David Cameron will be speaking at Harry Hartog bookshop in Woden on Tuesday, August 16, at 6pm (6.30pm start).

He will also be doing an event for the Canberra Writer's Festival at the National Library of Australia (Ferguson Room) on Sunday, August 28, at noon.