Holly Madison's memoir, "Down the Rabbit Hole," doesn't just dish on her own time in the Playboy mansion as Hugh Hefner's girlfriend (well, the "main" squeeze of his three) and the E! show "Girls Next Door," which ran from 2005 to 2009. Madison lets it all out and writes that she and Kendra did not get along behind closed doors. Madison even calls the "Kendra On Top" star "the fakest person I've ever met," according to E! Online.

"Despite my attempts to befriend Kendra, she continued to push me away," Madison wrote in her bok, according to E!. "Hungry from her own 'team,' Kendra desperately tried to make each new Playmate who arrived at the mansion her friend - and her friend alone."

Wilkinson moved into the mansion in 2004. The now 29-year-old mother of two was 19 years old at the time. "At 19 years old, Kendra was stuck with a 9 p.m. curfew, a 78-year-old boyfriend, and a stricter set of rules than she had ever had at home," Madison wrote. "And now, adding insult to injury, she was finally realizing that she wasn't as special as Hef made her believe. She was just another blond girlfriend - and life at the mansion wasn't all she imagined it to be."

Madison wrote that she was a bit jealous of Wilkinson's "sense of entitlement." Madison was the main girlfriend, but probably the meekest, and Wilkinson had a "hustler mentality." Madison said that Wilkinson told Hefner that she was a college student - Hef was not a fan of strippers - and she asked for "the really big room." "Here was a rookie who had just gone all the way with an old dude and her only concern was how big her room was going to be," Madison said, according to People.

What happened that brought all this rage to a boil? "In Kendra's book 'Sliding into Home,' she describes Hef asking her to be a girlfriend and handing her a house key before he invited her up to the bedroom," Madison wrote. "Now, I don't know if Kendra is trying to sound extra-desirable, innocent, or if her memory is just super rusty, but of course that's not how it really went down. Hef isn't stupid. He never asked anyone to become a girlfriend before they joined him in bed. And he never made a habit of carrying around extra sets of room keys."

Apparently, Madison wasn't the first Playboy Bunny to let the cat out of the bag. "Kendra had apparently given an interview to a tabloid explaining that she wasn't friends with either of us [Madison and Bridget Marquardt, Hef's third girlfriend at the time] as if she were somehow better than everyone else...," Madison said, according to E! Online. "Of course I wasn't going to stoop to her level and address this only on social media, so I decided to text her how I truly felt: that she was a coward and that she tried to act like the 'real' girl on TV, but she's the fakest person I've ever met - and that if she had a problem with me, she should have confronted me like an adult instead of just going silent.

"After that, I deleted her number from my phone. Kendra and I haven't spoken since, and I have to say, I don't miss her."

Ouch.

For more on Madison's memoir and the dark side of her seemingly-enchanted life at the mansion, check out HNGN's article by Emily Morgan.