pt. 1. Calendar in theory
ch. 1. Calendar
ch. 2. Astronomical background
ch. 3. Time and the clock
ch. 4. Writing and libraries
ch. 5. Numbers and arithmetic
ch. 6. Variety of calendars
ch. 7. Reform of the calendar
pt. 2. Calendars of the world
ch. 8. Introduction
ch. 9. Prehistoric calendars
ch. 10. Calendars of Babylon and the Near East
ch. 11. Egyptian calendar
ch. 12. Calendars of China and East Asia
ch. 13. Calendars of India
ch. 14. Mayan and Aztec calendars
ch. 15. Four European calendars
ch. 16. Roman and Julian calendars
ch. 17. Jewish calendar
ch. 18. Islamic and Bahái︣ calendars
ch. 19. Gregorian calendar
ch. 20. French Republican calendar
ch. 21. Week
pt. 3. Calendar conversions
ch. 22. Calendar conversions
ch. 23. Mathematical notes
ch. 24. To calculate the day of the week
ch. 25. Conversion of regular calendars
ch. 26. Jewish calendar
ch. 27. Mayan calendar
pt. 4. Easter
ch. 28. Short history of Easter
ch. 29. Date of Easter Sunday
ch. 30. Book of hours.