Legendary editor Jane Pratt is writing a tell-all memoir

It happened to her!

The editor who perfected the wrenchingly confessional first-person essay is bringing us the ultimate wrenchingly confessional first-person essay: Jane Pratt is writing a memoir.

And sources who have read a proposal for the book tell Page Six that she’s planning just the kind of deeply dishy, soul-exposing, fight-picking, flaw-finding page-turner that she famously commissions.

We’re told that, among other things, the book will give the “It Happened to Me” treatment to her career collisions with Si Newhouse and Anna Wintour, her romance with Michael Stipe, her many celeb friendships including those with Chloe Sevigny, Courteney Cox, Drew Barrymore and Courtney Love, and her various personal traumas.

Publishing spies also say that she plans to finally tell the story of Cat Marnell from her perspective.

Marnell was a beauty editor at Pratt’s era-defining XOJane website while her life was sliding into a mire of addiction and mental ill-health, an experience that became Marnell’s cult memoir, “How To Murder You Life.”

Pratt founded beloved, feminist teen magazine Sassy at 24 years old, and launched much-missed Jane magazine in 1997, part of Newhouse’s Condé Nast empire. After XOJane, she launched her current project, Another Jane Pratt Thing.

We’re told that the chapter titles in the proposal are a nod to her legacy with the first-person genre.

They include, “I Was Banished to an Institution in a Faraway Land,” “I Cut Myself on Purpose,” “I Had a Panic Attack While Giving a Speech and it Hospitalized Me,” “The Moral Majority Killed My Baby,” “My Dad Was Murdered,” “I Was Not In Love But Got Engaged Anway,” and “I Took Benzos While Pregnant.”

It will be her third book, joining 1995’s “For Real: The Uncensored Truth About America’s Teenagers” and 1997’s “Beyond Beauty: Girls Speak Out on Looks, Style and Sterotypes.”

After a recent run of media mogul memoirs including those of Graydon Carter and Barry Diller, we expect this to be the must-read media book of… whatever year it comes out… and for it to leap onto the Condé Nast obsessive’s required-reading list along with Tina Brown’s “Vanity Fair Diaries,” André Leon Talley’s “The Chiffon Trenches” and Dana Brown’s “Dilettente.”