Henri Cestia was born in 1949. Trained as an engineer and IAE Paris-Dauphine, he began in the 1990s to digitize the family genealogy and then continued the généalogical work initiated by his parents on the Cestia branch. In 2011, he created a website and expanded his research to Cestia around the world. Until the first edition de Hasard et Volonté in 2018, he relentlessly searched for documents and information on the Cestia that he published regularly on his website.