"Memoranda on the Maya Calendars Used in the Books of Chilan Balam" by Charles P. Bowditch is a scholarly publication written in the early 20th century. The book delves into the intricacies of the Maya calendar systems referenced in the historical texts known as the Books of Chilan Balam. It explores the calendrical calculations and methods used by the Maya civilization and compares them to other dating systems, aiming to clarify and enhance understanding of historical timelines and significant events within the Maya culture. In this work, Bowditch meticulously examines various passages from the Books of Chilan Balam, such as the referenced death of Ahpula in 1536, highlighting discrepancies in calendrical calculations and various methodologies for counting time. He discusses the concept of the katun, its possible lengths, and the significance of corresponding dates in the inscriptions found at archaeological sites like Copan and Quirigua. The book is a detailed analysis that seeks to reconcile different interpretations of Maya timekeeping and provides insights into the historical context of the Maya civilization, showcasing Bowditch's dedication to understanding their complex system of calendars and its implications on the timeline of their history. (This is an automatically generated summary.)