An excerpt from Bilton’s new book, Hatching Twitter: The untold story of Twitter’s true origins—and the contributions of Noah Glass, the co-founder who disappeared from the picture:

“What Glass didn’t know was that Dorsey was the one who wanted him out. Perhaps it was because he sensed vulnerability or perhaps it was because Glass was the only person who could rightly insist that the status updater was not Dorsey’s idea alone. Whatever his reasons, Dorsey had recently met with Williams and threatened to quit if Glass wasn’t let go. And for Williams, the decision was easy. Dorsey had become the lead engineer on Twitter, and Glass’s personal problems were affecting his judgment. (For a while, portions of the company existed entirely on Glass’s I.B.M. laptop.) After conferring with the Odeo board, around 6 p.m. on Wednesday, July 26, 2006, Williams asked Glass to join him for a walk to South Park. Sitting on a green bench, Williams gave his old friend an ultimatum: six months’ severance and six months’ vesting of his Odeo stock, or he would be publicly fired. Williams said the decision was his alone.”