His first novel, Le voyage d'Hector ou la recherche du bonheur ("Hector's Voyage or the Search for Happiness"), was very successful in France as well as other countries such as Germany. It is a book on psychology written for ordinary readers; it tells the story of Hector, a psychiatrist, who travels around the world in search of what it is that makes people happy. The book is written in a simple, humorous style, and gives psychological advice and thought-provoking impulses without even touching dry theory.
Lelord continues to publish novels dealing with similar topics which are written in a similar manner.
Following its European success, Penguin Group (USA) acquired the rights to publish Lelord's debut novel in the United States. Hector and the Search for Happiness was released on 31 August 2010.
This was followed by Hector and the Secrets of Love on 1 January 2011 and Hector and the Search for Lost Time on 31 July 2012.
A film adaptation of Hector and the Search for Happiness starring Simon Pegg as the title character was released in 2014.
Bibliography
La gestion du stress (1998), with Christophe André and Patrick Légeron
Liberté pour les insensés (2000)
Comment gérer les personnalités difficiles (2000), with Christophe André
L'estime de soi : S'aimer pour mieux vivre avec les autres (2001), with Christophe André