Every cent from book sales is donated to Starship, and the previous three books - all illustrated by Mealamu - have helped raise $80,000 for the children's hospital.
Mealamu said completing the illustrations had been tough this year because of a certain tournament that had kept him busy.
"I finished the last illustrations in the third round of [Rugby World Cup] pool matches...but it was nice to be able to go home and take your mind off the World Cup."
He produced an illustration for each of the eight stories, and said while some took only a couple of hours, "there are some that just don't come to you for a couple of days".
The Young Authors' Challenge that led to the book's production saw more than 100 entries, and children's authors Paula Green and John Parker helped tweak the winning copy for publication.
Some stories were written by individual authors, while others were a group efforts by classes.
The book's more than 100 young authors sat cross-legged as Mealamu read them a passage from the book at Starship Hospital yesterday.
He answered questions such as "do you like being a rugby player?" and had his greeting echoed back to him en masse: "Good afternoon Keven".