New Delhi, May 16 : What are periods? And why is it such a big secret, 11-year-old Aditya really wants to know. Ever since Rhea didi began getting brown paper packages, there's been something that no one is telling him. Mama turns red, Pa chokes on his coffee and Dadi has steam coming out of her ears! While Naveen and Vinay, his classmates, add to the confusion and show him a napkin that soaks ink, Aditya is left wondering why does his sister not just talk to him? All of this is only making little Aditya even more curious... Seriously, what is the big deal? Told with a lot of humour and heart, this conversation starter, "What's the Big Secret" (Puffin), a full-colour illustrated book on periods, helps everyone, especially boys, understand the bodily process and quell their curiosity. It's a much-needed book that will help expel the stigma attached to the concept, "What's the Big Secret" by Sonali Shenoy, essentially illustrated by Annushka Hardikar, will help parents engage in difficult conversations about growing up with their children. Sonali Shenoy is a writer and a journalist. "The Dog Who Taught Me Math" was her first children's book. She is currently raising two money plants - Oprah and Ellen. /IANS