Pippa Middleton is the younger sister of Catherine, Duchess of Cambridge and on Amazon's website in the About the Author section:
Pippa Middleton is the editor of The Party Times, an online party magazine from Party Pieces, the UK's leading online party-supply company, founded in 1987. She has organised many events during her career at London-based events company Table Talk, for luxury brand and corporate companies as well as private parties.Celebrate: A Year of Festivities for Families and Friends is Pippa Middleton's first book and according to the book description on Amazon, her new book "reveals the secrets to hosting a successful party with recipes, tips and detailed instructions on how to throw a memorable event."
In a recent Los Angeles Times Article titled Are you ready to party like Pippa Middleton? by Carolyn Kellogg, Pippa Middleton "was paid a reported $650,000" for Celebrate: A Year of Festivities for Families and Friends.