Gardiner, author of The History of B Company which is to be published this year, shared his own research into the battle.
Born in Whakatane, Gardiner was educated at Whakatane High School, Canterbury University and King's College, London.
His diverse career path has seen him serve as a professional soldier and senior public servant. For the past 20 years he has been a businessman and author.
In 1992 Gardiner wrote a military history on the 28 Maori Battalion using interviews and available archival resources.
In May 2016, he travelled to Greece and Crete to visit battle sites where the NZ Division fought in April and May 1941, matching the theory from his book with the actual locations of the battles.
Organiser and Rotorua Museum events and engagement co-ordinator Tory Williams said the talk went well.
"The chamber was full, we had whanau members from a range of soldiers.
"We were happy with the talk and the turnout."
Williams said the museum hosted the talk due to strong requests for it.
"Clearly there was a need and an interest in this type of event.
"A lot of the people we had there were people who don't usually come to our other talks."