In the book, Mkhitaryan discusses his final months at United, which ended with him joining Arsenal.
He recalls his relationship with then-manager Jose Mourinho, saying that Mourinho had been critical of him since he joined the team.
Mkhitaryan wrote that Mourinho called him "s***" and that he lost his temper in response.
During training sessions, Mourinho was silent towards Mkhitaryan, but sent him messages via WhatsApp, asking him to leave the team.
Mkhitaryan said that the situation became "grotesque" and that he would only leave if he found a new team or if the summer transfer window opened.
As the situation unfolded, Mkhitaryan's response to Mourinho's messages changed, with him eventually telling Mourinho to talk to his agent, Mino Raiola, if he wanted to discuss a transfer.
Mkhitaryan has joked that the situation was resolved, saying "And everyone lived happily ever after."