During her nine years in Parliament, Waring kept every paper that crossed her desk, including National Party papers and newsletters from women's organisations asking for support.
The Political Years, which took her eight years to write, is compiled of stories gathered from 400 cartons of papers collected during her time in Parliament.
"All of these cartons hold all these stories that really give the texture because I wanted the book to be about us, not about me."
Her book is a very different history of New Zealand over a 10-year period, she said.
"So you'll hear voices you've never heard before across that. I say it's not a his-story, we're challenging the traditional paradigm of what his-story is about. This is not his-story."
At the Zonta event, Waring read sections from the book, including a list of what women's organisations asked for during her time in Parliament.
This included te reo Māori being taught in schools as well as more New Zealand history.
"What amazes me is we haven't got half of them yet," Waring said.
Waring was well-known for crossing the floor on a number of issues in support of the Labour Opposition.
One evening, she said, she crossed the floor 18 times over a piece of industrial relations legislation.
"There are things I look back on and I feel very proud to be part of them."
Waring said universal superannuation was extremely important, even more so in 1977 as for many women it was the first independent money they had ever had.
She said she loves the National Parks Act 1982 as it embraces what New Zealanders feel about their natural environment and praised Michael Minogue's work on the Official Information Act.
"When you don't have a written constitution, you need all kinds of safeguards - and he led that and from the backbench so to achieve something like that is extraordinary."
In the book, Waring tells stories of the good and bad days she experienced, including the day protesters were removed from Bastion Point.
"You can go into Parliament with self-respect but there are many days when you feel self-contempt.
"I fought the bullying, fought the abuses of power, but I was still at the end of the day complicit, you know, by being there, so those things were hard. I was very, very lonely."
She said her constituents from Raglan and Waipa kept her going by staunchly defending her.
"The other thing that got me through every day were the letters that came from women and men.
"It just kept me going and you think, this is why you do it."
Waring said she was grateful a younger generation was now leading New Zealand's Government.
She believes health has been hugely underfunded in recent years and violence against women and equity in pay are still major issues.
Waring was in Parliament for what she called "the dreadful abortion debate" in 1978 and is shocked that it has taken until 2019 to readdress women's reproductive freedom.
"There are many lives that could have just had quite different trajectories that have been suffocated over the years with these different changes just not proceeding."
She encouraged young voters "to get out there and be active" with their voices.
Waring left Parliament in 1984 and moved into academia, gaining a PhD in political economics and is now a professor at Auckland University of Technology.
More than 60 women attended the Whanganui event which raised funds for Perinatal Anxiety and Depression Aotearoa.
