The book "Was the initial day of the month of May marked with zero (or twenty) or one?" written by Charles P. Bowditch and explores the complex issue of the Mayan calendar system. The author examines historical sources and archaeological discoveries to solve the riddles related to the calculation of the beginning of the month of May. The book details various perspectives on this issue, helping the reader to better understand the complex aspects of the Mayan calendar. The author offers his own theories and arguments, which makes this book interesting for anyone interested in history and archaeology.