In his best-selling 2010 memoir, ''Portrait of an Addict as a Young Man,'' the author recalled how crack cocaine destroyed his life. Now, in ''Ninety Days,'' the book agent, 41, describes what happened next

In Ninety Days you catalog your attempts to stay sober after rehab. Was writing that a different experience from penning Portrait of an Addict as a Young Man, which dealt with your days as a regular crack user?
The second book bloomed out of the writing of the first. When I finished Portrait I didn’t have that sense of completion. So I just didn’t stop. When I finished Ninety Days I felt finished. But there are miserable moments in both. There was plenty of misery to spread around.

Near the start of the book you recall how, after leaving rehab, you owed money to drug dealers. They seem to have been very patient about you paying them. I expected a chapter in which you got your kneecaps broken.
Me too. Well, I didn’t expect a chapter — I just expected my kneecaps to be broken. But these dealers are used to seeing people hit bottom and then clean up and then buy more drugs. Nine times out of 10, they’re going to be repaid because somebody who owes them money is going to call them for drugs.

Ninety Days opens with a Henry Miller quote: ”Forget yourself.” Why?
My experience is that alcoholics and addicts suffer from an exaggerated self-consciousness. People deal with that anxiety with alcohol and drugs. All that worry lifted when I became involved with other alcoholics and addicts who were in recovery. That’s what that quote speaks to.

Near the end of the book you finally achieve 90 days of sobriety. May I ask how long you have been sober now?
As it says in the book, after five and a half years, I drank. That was after being away from New York for a month, without the community of my sober friends. I was in a hotel alone and I picked up a glass of vodka. I didn’t do drugs. I came back to New York and immediately resumed going to meetings. It’s been, like, a year.