Asked if she ever imagined her 80th birthday celebrations would include appearing at a prestigious literary event, Cowley admits she never expected to make it to 80.
"We were always taught three score years and 10 was the limit but life has changed," she says.
Believing children should be involved in an international congress about literature for them, Cowley will make a keynote speech with four children's choirs singing between each section of her talk.
"Most meetings about children's books are dominated by adults so it felt right there should be some children there," she says.
Then, at the free Storylines Auckland Family Day on Sunday afternoon, Cowley will celebrate her 80th birthday with a giant cake, a performance of one of her books by South Auckland schoolchildren and music.
When she returns home to Featherston, she will resume writing a libretto for a new children's opera - friend and acclaimed NZ composer Gareth Farr is writing the score - and readying herself for the launch of the third book in the much-loved Snake and Lizard series. Cowley is also about to start a two-year course in Ignatian Spirituality.
In a candid interview with TVNZ's Sunday, she spoke of the importance of spirituality in her life. Cowley also talked about her sometimes fraught childhood, and a suicide attempt when her first husband left her and took their four children with him. But Cowley says the toughest times in her life have been the most important because they have taught her valuable life lessons.
• IBBY starts on Thursday and ends with the Storylines Auckland Family Day on Sunday. Storylines, an annual event, also includes a South Auckland Family Day on Saturday, August 20 at the Mangere Arts Centre.