Kim Kardashian, Khloe Kardashian and Kourtney Kardashian

Why did the Kardashian sisters decide to write about their childhood in their new book, Kardashian Konfidential?

"[Keeping Up with the Kardashians] was developed when we were older and we wanted everyone to see where we were before, and how we grew up," Khloe, 26, tells TVGuide.com

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Although the book offers beauty tips about waxing and how to  strike the perfect pose, it also includes lots of family photos and allows the sisters to relive some of their favorite memories. The girls agree their favorite part is the Christmas chapter.

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"My mom has always, since we were born, thrown a Christmas eve party," Kim, 30, says.  Adds Kourtney, 31: "She was just about to stop having the elves come... but then she said she couldn't let them go. ... So now she guarantees they're here for [my son] Mason."

In the video interview below, the Kardashians talk more about Kardashian Konfidential, how they hate the word "fame," and why they're really not that cool.