The reclusive heir to the Saint Laurent fashion fortune is said to be unhappy with a new book.

Garden designer Madison Cox, 59, is a key figure in “Loulou & Yves: The Untold Story of Loulou de La Falaise and the House of Saint Laurent”[1] by Christopher Petkanas, out Tuesday from St. Martin’s Press.

The handsome Cox got married to Saint Laurent’s longtime business partner, Pierre Bergé, a few months before Bergé died this past September at the age of 86, leaving Cox an estate believed to be worth more than $1 billion.

Petkanas was set to speak next month at Boscobel House and Gardens in Garrison, NY, but the event was mysteriously canceled, and the author believes friends of Cox lobbied to quash it.

“I had a signed contract, and they pulled the rug out from under me,” Petkanas told me. A spokeswoman for Boscobel said: “We came upon an unanticipated conflict and had to cancel the lecture.”

A spokesman for Cox said he was “unavailable for any comment.”

Cox is also director of the Saint Laurent museums in Paris and Marrakech,[2] Morocco, and president of the Pierre Bergé-Yves Saint Laurent Foundation.

“Madison is enormously rich and has a huge budget at his disposal. His friends are fiercely protective,” Petkanas said.

Cox might be upset because the book adds color to the rumors that despite his marriage to Bergé, he has a longtime boyfriend, Jaimal Odedra. The marriage took place possibly to ensure Bergé’s will couldn’t be contested.

Cox’s friends were unable to put the kibosh on the book’s Tuesday launch at Marc Jacobs’ Bookmarc store on Bleecker Street, or on Petkanas’ talk with Fern Mallis the following night at the 92nd

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