How Jessica Simpson, whose billion-dollar fashion business exists without her ever pinning a dress, to Kanye West’s epic Parisian fashion fail (hilariously described, by the way) is the stuff of veteran scribe Teri Agins' new book, “Hijacking The Runway, How Celebrities are Stealing the Spotlight From Fashion Designers,” ($28, Gotham Books).

The tome -- detail rich, painstakingly researched and lively -- investigates celebrity sway in the marketplace and focuses on how popular culture, social media and all-out star power of big names like Simpson, Sean Combs, Jennifer Lopez, Justin Bieber and Lady Gaga have irrevocably changed the fashion game. Reaching back to the likes of Audrey Hepburn, Elizabeth Taylor and Gloria Swanson, Agins sheds light on how luminaries have increasingly harnessed their glow and turned attention and sales away from traditional purveyors of fashion ... serious designers.  

Celebrity influence on fashion is not necessarily negative, writes Agins pointing to Victoria Beckham and Mary-Kate and Ashley Olsen as having earned real deal designer cred, but she is critical of others  -- many from the reality show world -- including several of Bravo’s housewives and the Kardashian clan.

A breezy and authoritative read, Agins covered the business of fashion for almost 30 years at The Wall Street Journal and continues to write the advice column “Ask Teri.”  In 1999 she wrote “The End of Fashion,” about how mass-marketing and fast fashion had invaded the world of high fashion. 

“No one is writing books like this today,” Agins says.  “Fashion books are more often about Chanel, or Diana Vreeland, or a dead designer or the 100 top dresses in the world.  But it is clear that something has happened to fashion and that’s what compelled me to write this … to connect the dots.  It was a fun challenge.” 

And it’s a fun read. The 272-page hardcover book, which features 60 photos and a color insert, hit the shelves in early October, and is available at bookstores everywhere.