Gabor Maté is a Canadian practicing as a physician in Vancouver. He is of Hungarian, Jewish descent, and his experiences of the Jewish Holocaust—in which he lost two grandparents to the death camp at Auschwitz—are one of his focal points as he talks about childhood trauma in relation to addiction.

During the writing of In the Realm of Hungry Ghosts, Maté is the head physician at the Portland Hotel, a housing project for addicts. He chose to write the book because he has insight into the nature of addiction, childhood trauma, and obsessive personality traits. Through the book, Maté gives examples of his own addictive behaviors and contrasts them with those of the drug addicts he serves.

Maté is a compulsive shopper and a self-described workaholic. He does not see his behaviors as markedly different from those of drug addicts, although he often receives a reward for his compulsions, while addicts destroy themselves with theirs. He encourages readers to be suspicious of the so-called War on Drugs, and to think of the status of addicts as detrimental to their recovery. Maté values compassion and self-scrutiny, citing them as master values with which to gain the awareness that will lead to empathy with substance addicts.