The story of the Jewish calendar begins with the Exodus from Egypt- more than thirty-five hundred years ago. Over the millennia, the twelve individual Jewish tribes coalesced into the nation of Israel, adopting, adapting, and ultimately developing their own religious calendar, which has withstood the vagaries of the ages. At one time an observational calendar based on the visual sighting of the New Moon, the Jewish calendar is now a sophisticated calculated calendar based on average lunation time, while remaining true to its ancient past. A small council of rabbis guarded the secret instructions for constructing the calendar, until the mid-fourth century C.E. when, due to repressive acts and ultimate dissolution of the Jewish Court by Roman emperors, Hillel II, President of the Jewish Court in Babylonia, revealed those rules, so that Jews anywhere are able to construct their religious calendar. Today, those rules and how to apply them are, in general, neither well known, nor well understood. In The Jewish Calendar: History and Inner Workings, Second Edition, author and award-winning teacher Fred Reiss continues with the beliefs and patterns established in the first edition - clear explanations, practical examples, and chapter reviews with problems and answers. Using simple arithmetic, Reiss explains the basic details and fundamentals of the Jewish calendar. Some things new to the second edition are: The Jewish calendar, like the civil calendar, works in cycles, the most prominent of which are the sixty-one unique nineteen-year cycles, dictating, for instance, when common and leap years occur. These cycles are aperiodic, they lack a discernible pattern of appearing, repeating, vanishing, and reemerging. A new chapter is added to illuminate and resolve this mystery. We take the dates for the start of the seasons for granted. Spring, for instance, always begins on March 20 or 21, but not so in the Jewish calendar. Ancient methods are employed to determine the beginning of the seasons, one developed by Mar Samuel and one by Rabbi Ada. A new chapter solely focuses on explaining, clarifying and teaching how to use these approaches. Also new in The Jewish Calendar: History and Inner Workings, Second Edition are methods for converting Jewish dates to civil dates and vice versa, allowing for the construction of corresponding Jewish and civil calendars. The Jewish Calendar: History and Inner Workings, Second Edition answers many questions, including: How do you compute the start of the High Holy Day Rosh Hashanah? Why is Rosh Hashanah often postponed? Why have the rabbis condensed seven days into four days? The civil calendar is either 365 or 366-days long, why does the Jewish calendar have six different year lengths? The Julian calendar repeats every twenty-eight years, the Gregorian calendar every four hundred years, why does it take 689,472 years for the Jewish calendar to repeat? Why does the Jewish calendar's nineteen-year cycles act so strangely? All calendars have errors, what are the Jewish calendar's errors and what do they affect? Are there any ways to mitigate the errors? What are the steps for constructing a Jewish calendar? Each chapter ends with a review and a set of exercises, the answers to which are provided. The Jewish Calendar: History and Inner Workings, Second Edition reveals the structure, content, and interconnections within the calculated Jewish calendar in a format for the casual reader or as a textbook for self-instruction. It is a valuable resource for understanding the complexity of the Jewish calendar.