Whether one is interested in the Iditarod or Ramadan, Holidays, Festivals, and Celebrations of the World is the premier source of information. The third edition contains nearly 2,500 observances from the U.S and more than 100 other nations. New content includes more than 400 brand-new entries, among them independence and national days around the world; religious holidays from the Muslim, Sikh, Jain, and Zoroastrian denominations; Native American celebrations; an expanded section on calendar systems; and a perpetual calendar.

The dictionary is arranged alphabetically by the name of the celebration and ranges from Aban Parab, at entry number 0001, to the Zydeco Music Festival, at number 2496. Entries include the name of the celebration, time period, a brief description, contact information, and sources consulted.

Changes from the previous edition include the removal of the introductory "Millennium" chapter and the "Web Sites on Holidays" appendix. The remaining appendixes have been updated. The index section also received an overhaul. There are now three indexes — chronological, special subject, and general. The chronological index has two parts, "Fixed Days and Events Index" and "Moveable Days Index," which lists entries observed according to the non-Gregorian calendar. The "Special Subject Index" is arranged in six categories — "Ancient/Pagan," "Calendar," "Folkloric," "Historic," "Sporting," and "Promotional." Finally, the general index combines four indexes from the previous edition and is arranged alphabetically by keyword and includes proper names.