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While a lot of celebrities opt to spend their money on fancy cars, luxurious vacations, and a closet full of designer clothes, Lena Dunham has a very different collection of valuables.

Dunham shared a picture on Instagram of what she calls her “newly minted prized possession,” but it’s nothing more than a simple book—Stephen Birmingham’s Life at the Dakota: New York’s Most Unusual Address, to be exact. While it’s a popular read, you can pick one up online for about $20.

What’s especially surprising is the fact that the 1996 book appears to be temporarily out of stock on both the Amazon and Barnes & Noble web site—either the book is still incredibly popular (perhaps thanks to Dunham’s post), or Dunham’s copy is one of the few left.

Judging by the comments on her post, people are pretty jealous. “Ooooh!! You have a copy with the dust cover. Jealous. I own this book and it remains one of my most prized possessions [sic],” wrote one follower, while several others commented about how they would love a copy of their own after seeing hers.

For those who aren’t familiar with the Dakota building, it’s arguably one of the most famous buildings in New York City. The Dakota was once home to the late John Lennon and his wife, Yoko Ono. In fact, this is where the former Beatle was shot and killed. (Yoko Ono still lives there.)

Today, the building houses some of the most exclusive and high-end co-op apartments in Manhattan, with units selling for millions. However, the Dakota is still riddled with stories of ghost encounters (including Lennon’s ghost) and rumors about thousands of dollars stashed under the floor. It also reportedly has no fire escapes, its own in-house power plant, and an extremely intense application process that has rejected even A-list celebrities.

Come to think of it, it’s no wonder the book is sold out—maybe Dunham’s copy really is a prized possession after all!