In his dark days, Dallas lawyer Brian Cuban would snort lines of cocaine in his law firm's bathroom to keep going, masking the hangover from his night spent drugging and drinking.

In recovery for 10 years for substance use disorders, bulimia, depression and other mental health issues, Cuban, who worked as a solo and of counsel at small firms, stopped practicing law in 2007 and devoted his life to writing and public speaking around the country to help others with drug and alcohol addiction. His new book “The Addicted Lawyer: Tales of the Bar, Booze, Blow and Redemption,” goes into extreme detail about problems that started in college, progressed throughout his legal career and led to recovery.

We interviewed Cuban—who graduated in 1986 from University of Pittsburgh School of Law and whose billionaire brother Mark Cuban owns the NBA team the Dallas Mavericks—about his addiction and recovery. Here are his answers, edited for clarity and brevity.