The cocktail dress rivals only the LBD for importance in a girl's closet. The cocktail is feminine, fun, and sexy, and made for a night out — what's not to love about that? And so it's only fitting that it get an entire book devoted to its history, curated and written by Style.com's Laird Borrelli- Persson. The Cocktail Dress traces the history of the piece, from its conception in the twenties to Dior's New Look interpretation to Audrey Hepburn's Givenchy number in Breakfast at Tiffany's to more recent couture looks. And, true to Borrelli-Persson's other image-heavy books, this one is filled with contributions by designers like Peter Som, Cynthia Rowley, and Isaac Mizrahi, and shows off dresses by Vionnet, Marc Jacobs, and more. And many of the contributors will be toasting the tome at the official launch tonight. Check out our favorite images from the book in the slideshow.