Even if you're not the bookish type, the rise of library tourism has much to offer the savvy sightseer.
The truth is that everyone except me has come to Oxford University's Bodleian Old Library to hear about Harry Potter.
The magnificent working library - the centrepiece of 26 libraries across Oxford collectively known as the Bodleian Libraries - offers two public tours daily (three on Wednesdays and weekends) and it takes me a while to realise that my fellow muggles are all Potterheads. While the group listens dutifully to our guide's slightly stilted commentary on the 400 years of Bodleian history, all the tour group's questions relate to the library's role as Hogwarts Library in the first Harry Potter movie, Harry Potter and the Philosopher's Stone.
"They shot inside the library for 43 hours nonstop," says the guide, "instigating the fury of academics who couldn't study because of them. The funny thing is that they filmed the background here, then re-created everything in the studio."
The guide shows a still from the movie and asks us to spot an anomaly. A young woman correctly identifies actor Daniel Radcliffe burning a lantern in the darkness. In fact, library members are bound by an oath "not to bring into the library, or kindle therein, any fire or flame".
"The lantern was created by a computer in postproduction," says the guide.
We are also led around the 15th-century School of Divinity which is now a part of the Bodleian and features as Hogwarts' Hospital Wing in the first movie and various other locations in the sequels, including the ballroom in Harry Potter and the Goblet of Fire.
While our 30-minute tour is technically library tourism, we are not a group of library tourists. "Library tourism" is an apparently growing interest whose creative hub is the website Library Planet, run by Australian academic Stuart Kells, author of The Library: A Catalogue of Wonders. Kells says that more than half the contributors to the website would be librarians - generally visiting other people's libraries - but many are historians, photographers or "just professional people who like visiting libraries".
While travellers might not come to town specifically for the library, savvy sightseers with one eye on culture and the other on amenities might drop into an exhibition at a public library when visiting attractions nearby. Entry is free, everyone is welcome, and libraries offer a chance to rest, plug in your tablet, recharge your phone and use a clean bathroom. They're also ideal places to shelter from the weather, since books and documents need to be stored at a steady temperature: If it's cold outside, it's warmer in a library; if it's too hot in the open, a library is a comfortable spot to chill.
Some libraries might say as much about a country as its literature. The State Library of NSW has a rooftop bar (open evenings, Wednesday to Saturday) with views of Sydney Harbour, making it one of the few libraries in the world where you can sit in the sun and grab a beer (or a glass of wine or a cocktail). Meanwhile, the Helsinki Central Library Oodi in Finland has a unique draw as the world's only library with a sauna.
A surprising number of coastal cities have libraries (sometimes technically municipal book exchanges) on the beach. The United Arab Emirates has 24-hour libraries at Kite Beach, Al Mamzar Beach and Jumeirah Beach. In Israel, Tel Aviv has a council library cart at Metzitzim Beach. Albena Beach Library at a Black Sea resort in Bulgaria boasts 6000 books in 15 languages. In Sydney, Watsons Bay Library on Marine Parade is only a two-minute walk from Gibsons Beach and offers bay views from the adjacent Tea Gardens.
If you're sightseeing in Tokyo with the littlies, you might want to take a break from the museum quarter at Taito City for a stop off at the International Library of Children's Literature, if only to sit down for a snack at its dessert-led café. There's also a large play area and a museum that mounts temporary exhibitions. The collection includes Heidi in German, Tintin in French, Mem Fox's Possum Magic and, brilliantly, Hilary Bell and Antonia Pesenti's Alphabetical Sydney ("C is for cicadas ... G is for garage sales").
I recently met a mate in London's British Library, a red-brick complex that was once denounced by a parliamentary committee as "one of the ugliest buildings in the world", and described by Prince (now King) Charles as "a dim collection of sheds groping for some symbolic significance" with a reading room like "the assembly hall of an academy for secret police".
The great and the good missed the old British Library, which had been part of the British Museum. The library's modern incarnation, in a converted goods yard opposite St Pancras Station, lacks the mystique and romance of the former site, but makes up for it in bathrooms, workspaces and reasonably priced food outlets (try the Terrace Restaurant). And there is still beauty, if you know where to look.
Some libraries might say as much about a country as its literature.
The King's Library, a huge collection of often handsomely bound Enlightenment-era publications assembled in the 18th century by George III, was once kept at Buckingham Palace, then under the dome of the British Museum, and is now installed in a soaring glass tower that rises through the heart of the British Library. Its holdings include a Gutenberg Bible and William Caxton's first edition of Chaucer's Canterbury Tales. A permanent exhibition of the Treasures of the British Library at the library's Ritblat Gallery showcases elaborate medieval illuminated manuscripts; handwritten lyrics by the Beatles; and one of the four surviving copies of the Magna Carta.
The British Library is one of two libraries that collects every book published in Britain: the other is the Bodleian. But this is a minor concern for my comrades on the Bodleian tour, who are more animated to learn that the chained books in the Restricted section of Hogwarts Library are actually shelved the wrong way round. At the Bodleian and elsewhere, where some of the most valuable works were once chained to the shelves to prevent theft, the books were always displayed edge-out to avoid tangling their chains.
Which goes to show that even if you only travel to trace the imaginary footsteps of Harry Potter, you might still learn something new about libraries.