The book "History of the Inquisition of the Middle Ages; Volume I" by Henry Charles Lee is a study of the formation and development of the Inquisition in the Middle Ages. The author examines the history of this institution in detail, starting with its appearance in the early Middle Ages and revealing the key events, figures and approaches that determined its functioning. Through the prism of careful analysis of sources and documents, the author offers the reader a broad overview of how the Inquisition affected society, politics, and religious beliefs of the Middle Ages. This book is considered one of the important works on the subject of the medieval Inquisition and is a valuable source for those interested in church history, religious conflicts and social transformations of past eras.