It’s one of the most impressive reference volumes in the world: the critically acclaimed Chase’s Calendar of Events. Founded in 1957, the book has come to feature more than 12,500 historical milestones, celebrity birthdays, astronomical phenomena, major festivals, sporting events, national holidays from every country on Earth, and more, and it has become something of a success story for how to do reference in the digital age. This year is the first that Chase’s will be published by Rowman & Littlefield’s Bernan Press, which acquired the title from McGraw-Hill in January. PW caught up with Holly McGuire, editor-in-chief of Chase’s for the past 12 years, to talk about the venerable publication and how it has adapted to the digital age.

Can you describe the effort that goes into compiling and updating this massive compendium? How has the work changed with the advent of digital technology?

I’m laughing a little, because the Chase brothers—Bill and Harrison—used to compile the book using index cards. So, luckily, no more index cards! These days, we have a mix of tools to compile data, and a lot of the process has been automated. We start working on new editions of Chase’s around November and usually finish up editorially in late July, so it’s a nine-month cycle. All ongoing sponsored events—usually festivals and events—are addressed with a renewal campaign, during which sponsors must confirm new information and sign off. And in addition to updating existing content, we do research for our Spotlight section, where we let our audience know what the really big things are. For example, in 2016, the 400th anniversary of William Shakespeare’s death will be a huge event. And, by the way, cofounder Bill Chase lives in Ann Arbor and turned 93 in April. He’s still an inspiration with every new edition.

As someone who has overseen this volume of special days for over a decade, any personal favorites?

Oh boy, I do have favorites! I can’t tell you how many voice mails I get in pirate talk on International Talk like a Pirate Day (September 19). I love International Hug a Medievalist Day (March 31), although I usually have to send my hugs virtually. I don’t know why, but I find Fill Our Staplers Day very charming. It occurs two times a year—the days after daylight saving time begins and ends, so November 2 is the next observance. Ada Lovelace Day, now observed internationally on the second Tuesday in October, celebrates women in science. Ada Lovelace was Lord Byron’s daughter. She lived from 1815 to 1852 and is considered a prophetess of the computer age. I also have a soft spot for literary days: Roald Dahl Day (September 13); Biographers Day (May 16), which celebrates the May 16, 1763, meeting of James Boswell and Samuel Johnson; and the granddaddy of them all, Bloomsday (June 16).

How has Chase’s adapted to the digital transition?

In my time here, we’ve gone from a book with a CD-ROM, to book and e-book, to now offering purchasers of the book or e-book access to an exclusive online website that enables them to search our data any way they wish—for example, marketers, we found, are especially interested in looking at festivals based on attendance. But customers do still value Chase’s as a print product. It’s 752 pages and still going strong. Basically, we just look to give customers what they want, and some customers still prefer the print book. But I should also add that the Internet has not dampened interest in Chase’s—in fact, in this digital age of social media we’ve actually raised our profile by reassuring the general public that, yes, someone you can trust is keeping track of all these special days.

That trust factor seems key—how important is managing the Chase’s brand?

Very important, and we have been paying more attention to communicating the value of the Chase’s brand—and our story—in the digital age. We try to communicate that we’ve been devoted to these observances and special days since 1957, and that people can trust us. We’re the most authoritative and comprehensive listing out there, and librarians, journalists, bloggers and marketers truly value that. I often see people tweet observances on the wrong day, or sometimes I’ll see people tweeting about holidays that don’t exist any more, what I call ghost holidays. Last month, the AP ran a story about an outfit that is charging people to register a national day. It’s difficult to keep track of everything. It requires constant vigilance. So, we try to let people know that we have extensive data, and that we focus on the days that people celebrate with the same authority that dictionaries record the words people use.