Simon & Schuster Children’s Publishing has announced the 16th book in Rachel Renée Russell’s middle grade series, Dork Diaries. Tales from a Not-So-Bratty Little Sister, which is due out on October 15 from the Aladdin imprint, will have a first printing of two million copies; the cover is shown here for the first time.

Russell began the series in 2009, which features the diary entries of middle schooler Nikki Maxwell as she navigates the highs and lows of adolescence. The series currently has more than 55 million copies in print worldwide.

“This series continues to appeal to young readers because it always hits straight at the heart,” Russell’s editor, Valerie Garfield, told PW. “There’s drama, struggle, and disappointment that’s universal, but these stories are the best at looking at those things, acknowledging them, and then taking a deep breath and moving forward with hope.”

In the new installment, Nikki is determined to help her friends with favors as they’ve done for her in the past, but she becomes overwhelmed by their requests and struggles with a health condition. Meanwhile, Nikki’s diary falls into the hands of her little sister and “fan favorite” Brianna.

According to Russell, introducing Brianna’s perspective was “kind of the plan all along. I’ve always been wanting to do another story where a different character gets a hold of Nikki’s diary and writes in it,” she said. “Brianna is a very popular character. She’s a little sweetheart, but she could also make Nikki’s life very difficult.”

Russell hopes her latest book showcases “ultimately how important both siblings are to each other.”