Just when you thought it was safe to get back in your khakis.

Three decades after “The Official Preppy Handbook” was first unleashed into bookstores, a follow-up called “True Prep” is in the works  hoping to reignite preppy fervor, update the mindset and explain just what it means to be a Chip or a Muffy in a Barack world.

The original volume, a slim, plaid-covered paperback that poked fun at the gin-soaked polo-shirt and loafer-wearing set, started out as a piquant bit of mockery but, like “Liar’s Poker,” a bestseller about bond traders, and “Wall Street,” the movie in which Michael Douglas declared greed to be good, it ended up being adopted as a kind of guidebook for those who wanted in.

The book sold 1.3 million copies, many to aspiring prepsters who wanted to know where to shop, what to wear and how to fully appreciate what it called “the virtues of pink and green.”

Among those buyers was Chip Kidd, one of the industry’s best-known book designers, who loved the original as a teenager growing up near Reading, Pa., where he attended public high school and adored topsiders. The handbook, he said, “changed my life.”