The son of a diplomat,[2] Gilbert Grellet graduated in 1969 from the École des Hautes Études Commerciales, France's foremost business school.

He was subsequently appointed Washington bureau chief, a position he held from 1983 to 1987 when he interviewed the President of the United States Ronald Reagan.

This book focuses on the life and work of French pharmacist Emile Coué, a pioneer of modern positive thinking.

Grellet has also authored historical works such as Aux Frontières du Monde, which explores the significant global explorations at the end of the 19th century and the beginning of the 20th century, based on articles from the French geographical review Le Tour du Monde, akin to the National Geographic magazine.

One of his more recent works, Un été impardonnable, edited by Albin Michel in 2016, examines the first three months of the Spanish Civil War and the controversial non-intervention policy adopted by the main Western democracies (the United Kingdom, France, and the United States), which refused to assist the Spanish Republic in the face of a military uprising supported by Hitler and Mussolini.