The task of this book is to illuminate the life path of the great Italian materialist thinker Giordano Bruno. The Soviet scientist Valentin Stepanovich Rozhitsyn (1888-1942) was engaged in the study of the life and work of Giordano Bruno for many years, but did not have time to finish his work. After his death, a lot of work on preparing the manuscript for publication was carried out by M.P. Rozhitsyna, who wrote some chapters based on the materials. Despite some fragmentation of this work, it illuminates an important moment in the history of Renaissance culture and serves to popularize the work of one of the outstanding fighters for the triumph of materialistic ideas, against the Catholic reaction.