Book lovers, collectors and librarians worldwide celebrate World Book Day on April 23.

In designating a day to celebrate and promote the enjoyment of books and reading, UNESCO selected April 23 for its symbolic significance, as the date William Shakespeare, Miguel Cervantes and Inca Garcilaso de la Vega all died. The International League of Antiquarian Booksellers chose the same date to commemorate rare books, celebrating the heritage of literature across the globe and the importance of preserving treasured texts.

At the University of Arizona Poetry Center, rare books have been at the core of one of the world's largest poetry collections since the center's founding in 1960. The center's executive director, Tyler Meier, compares rare books to the concept of biodiversity: The need to preserve artistic achievement and literary voices is just as vital to humanity as preserving the planet's endangered plant and animal species, he says.

The Poetry Center's L.R. Benes Rare Book Room houses and preserves important and unique books of poetry, including the center's prized 50,000th volume — book artist Charles Hobson's personal copy of his rendering of W.S. Merwin's "Trees."

Meier and other members of the Poetry Center's library staff discussed the rare book collection.

Q: What is the value of preserving rare books?

A: Meier: In collecting rare poetry books, the Poetry Center is expressing a value in a different, but parallel, endangered biodiversity — a kind of biodiversity of our most exceptional uses of language in their original or most artistic expressions. This biodiversity of exceptional uses of language is worth preserving as both a collective record of the culture and as independent but interrelated histories of an individual human experience of the world at a particular time. 

When we dignify, protect, celebrate and make accessible a book that documents an important part of who we are, we are also dignifying, protecting, celebrating and making accessible all that books profoundly make possible. And that includes the ability to see the world in all its wonder and complexity and mystery through another's eyes and, in turn, learn something about both ourselves and that which is bigger than ourselves—a relationship to knowledge that we will need for a challenge-rich future that we will have to forge together. 

Q: With information so readily available in digital form, how do the printed artifacts stand out?

A: Julie Swarstad Johnson, Library Specialist: In the same way that the content of a poem — the literal meaning of its words — is enhanced by a poet's careful use of sound or the arrangement of words on the page, the content of a book can be enhanced by the physical form the bookmaker gives it. One of my favorite books housed in the L.R. Benes Rare Book Room, "Sometimes I Pretend," by Naomi Shihab Nye, illustrates this idea perfectly.

Created by book artists Peter and Donna Thomas, "Sometimes I Pretend" initially looks like a box with a sprocket wheel on one side and a pencil stuck to another. But pull on the pencil, and a long sheet of handmade paper unfurls, with Nye's 44-word poem, "Sometimes I Pretend," printed on it in rainbow colors. The text of Nye's poem is effective on its own, but when presented as what can be called a "book object," it becomes a journey of discovery, surprise and delight for the reader.

Even for the more conventional books housed in the Rare Book Room, the physical, printed book conveys a layer of sensory information that can't really be replicated in a digital copy. The texture of the paper, the faint smell of the glue used for the binding, or the signature by a famous writer all contribute to your engagement with a physical book, giving you a sense of the book's life and meaning that you experience with your whole body.

Q: What are the Poetry Center's goals and guiding principles for collecting rare books? 

A: Wendy Burk, Associate Librarian and Library Director: When I started working at the Poetry Center as a library specialist back in 2008, our then-senior librarian Rodney Phillips taught me about selecting rare books by considering factors such as age, aura, beauty, scarcity, and uniqueness.

As far as age is concerned, the majority of the Poetry Center's collection was published after 1960, the year of our founding. However, we do have a number of treasured volumes printed in early centuries. 

Aura refers to a special mystique that attaches to a book and its author. One example that the Poetry Center hopes to acquire in the near future would be a first edition of Gwendolyn Brooks' "Annie Allen." The aura surrounding "Annie Allen" relates to the fact that it was the first book by an African-American author to win the Pulitzer Prize, in 1950.

Beauty might seem self-explanatory, but a visit to the Rare Book Room reminds you of the many different ways there are to make a book beautiful. We have beautiful letterpressed first editions with colorful woodcut illustrations and marbled endpapers, and we have beautiful sculptural books made out of recycled materials, such as a beach ball.

Scarcity, maybe the most straightforward way of determining if a book is rare, refers to the number of copies that were printed. Many of the books in the Poetry Center's rare book collection were published in editions of 100, 50 or even just 20 copies.

Lastly, the term uniqueness can be taken literally: Some of the books in the Poetry Center's collection were published in an edition of one. This means that only one copy was ever made, and the Poetry Center has that copy in its collection, which is often thanks to the generosity of the author or the artist. 

Q: What are some of the most notable items in the Poetry Center’s rare book collection?  

A: Sarah Kortemeier, Instruction and Outreach Librarian: There are many, but these are some of the most unique and valued items:

Anne Bradstreet's "Tenth Muse Lately Sprung Up in America [Poems 1758]" is the oldest volume in the Poetry Center's collection, generously donated by Charlanne Maynard. Bradstreet was the first New World poet to publish English-language poems, and she is widely held to be among the most important early American writers. This is an extremely rare and venerable edition of her poems.

Avi Kazen's "War Is Humane" is an artist's book that was produced by a University of Arizona student who drew inspiration for the piece from a class visit to the Poetry Center. Housed in a rusty paint can, with text collaged from magazines and an accordion-fold structure, this visually and structurally inventive book always captures visitors' interest.

"Inside Chance" is a limited-edition artist's book designed like a puzzle. The paper globe unfolds and refolds to reveal eight lines of poetry that can be read in 26 different ways. The text was composed by Arizona State Poet Laureate Alberto Ríos, and the book was printed and assembled by artist Linda Smith. 

Robert Frost's "Christmas Cards." Each Christmas between 1929 and 1962, Robert Frost selected or composed a poem as a Christmas greeting to friends and family; these were printed as limited-edition chapbooks by Spiral Press. The Poetry Center has several of these poem-greetings, some inscribed with personal messages to friends by the author.

LeRoi Jones, also known as Imamu Amiri Baraka, and Diane di Prima edited "The Floating Bear." This mimeo journal, published from 1961-1969, was edited by two young writers who later became giants of American literature. "The Floating Bear" featured a number of important 20th-century writers and artists at early points in their careers, and the Poetry Center is fortunate to include a nearly complete run of this journal in our Rare Book holdings.