Dorfman, 28, was on season 10 of "The Bachelorette" and got engaged on the show to Murray, 30, in 2014. The couple endured a public split in January.
Dorfman, one of New York City's newest residents, said she has been writing the "diary" book since her big move from Atlanta, reported People magazine.
"It is basically a tongue-in-cheek diary of my breakup but it's also kind of like the anti self-help book. I went through a very public breakup but it was also extremely private. I didn't share a lot of stuff and I feel like we, as women, don't share a lot of bad emotions that are associated with breakups and this book kind of defies that.