A look underneath Mansueto, UChicago’s famous ‘robotic’ library

I remember a few things about the University of Chicago campus tour I took as a high school senior–the liveliness of the Joseph Regenstein Library, the beauty of Rockefeller Chapel, the horror stories about all-nighters and finals–but what I recalled the most about UChicago was its massive underground library, serviced by robots, buried under a glass egg in the middle of campus.

The Joe and Rika Mansueto Library, known to the majority of the University community as simply Mansueto, is among the most widely recognizable places on campus. Standing starkly modern in the shadow of UChicago’s original Gothic-style buildings and the brutalist-style Regenstein, Mansueto’s distinctive glass dome can be found featured on campus posters, postcards, advertisements, social media accounts, and Zoom backgrounds. SciFi fans also might recognize it from a scene in the 2014 dystopian flick Divergent and the recently released 8th episode of the Apple TV+ series Dark Matter.

For me, Mansueto is where my voice gets louder with excitement when giving tours to out-of-towners. The underground library is the epicenter of numerous urban legends spun by students like rooms that trap first-years who miss one too many mandatory house meetings. It has long been a dream of mine to explore the library, learn more about its fascinating book retrieval system and explore parts of the library normally shut off to everyday access. Recently, that dream came true: David Bottorff, the collection management and circulation services librarian at Mansueto, led me on a tour of the facility, taught me about the library’s fascinating history and operations, and gave me an up-close look at its ingenious ‘robotic’ book retrieval system.

The origins of the Joe and Rika Mansueto Library

The area where Regenstein and Mansueto libraries now sit was once occupied by a 55,000-seat football stadium–the original Stagg Field. After University of Chicago President Robert Hutchins disbanded the University’s football team in 1939, the stadium was cleaned out and retrofitted, where appropriate, for scientific use. The field lay mostly empty until it was finally demolished in 1957, eventually being replaced by the Max Palevsky Residential Commons, the Regenstein Library, and a monument commemorating the 1942 moment when a group of scientists in a squash court under the old football field bleachers built the world’s first nuclear reactor.

Mansueto’s planners had a relatively small patch of land next to Regenstein to accommodate a building with a planned book capacity in the millions. German-born Chicago architect Helmut Jahn was chosen to design the library, mainly because of his unique proposal to move the library’s storage space underground.

In 2008, Joe Mansueto, the UChicago alumnus who founded the investment research firm Morningstar, Inc., and alumna and University of Chicago Trustee Rika Mansueto, recalled fond memories of long nights studying in the ‘Reg’ and honored their alma mater with a $25 million gift to support an expansion of the University’s library system. At the time, Regenstein Library–which opened in 1970–was running out of storage space for materials, and the Library wanted purpose-built laboratories for conserving and digitizing its collections. The Mansuetos’ generosity allowed UChicago to ramp up planning for the Mansueto Library, which opened in 2011 and was named in their honor.

Jahn’s underground design allowed for the addition of a spectacular glass-domed Grand Reading Room and allowed better control of the storage area’s temperature and humidity. Jahn’s famous glass ellipsoid dome is itself a marvel of design. Each glass panel has a unique size and only fits into its own specific slot. Construction crews carefully moved those 691 glass panels out of crates and into perfectly designed frames, like a giant puzzle.

The dome is compact, only measuring 35 feet tall, 120 feet across, and 240 feet long, and it is slightly angled so that it points towards the Nuclear Energy monument to the library’s north. Inside, everything is designed to maximize the comfort and focus of the library’s patrons. Eagle-eyed visitors may notice that the inside color of the glass dome changes from about 18 feet up from the floor. This is because Mansueto’s upper glass panels are dotted with ceramic frit, which improves energy efficiency and reduces glare for inside occupants. Additionally, the columns inside the dome don’t just serve an aesthetic purpose; they heat just enough of the dome’s air–from a level of about 15 feet and below, according to Bottorff’s estimates–to ensure a comfortable visit for patrons but not enough to waste energy or compromise the underground storage’s temperature controls.

Descending below Mansueto’s surface

Bottorff led me into a freight elevator and we descended 55 feet below ground, where I got a view of Mansueto’s famous automatic storage and retrieval system (ASRS). Five 50-foot-tall, automated cranes roll around on rails, each crane retrieving or storing one of 24,000 book bins, with each bin capable of carrying about 100 hardcover books. The bins are automatically hauled towards a workstation accessible to library staff members on the ground floor, precluding the need to physically travel downstairs to the underground storage area. After library staff take whichever items are requested by patrons from the bin, they use computers to direct the crane to put the bin back in storage.

While I saw this entire process play out underground, normal operations see book bin deliveries and retrievals occur at the ground level. Nine workstations similar to the one pictured above can be found on Mansueto’s ground level, all behind the circulation desk in an area referred to by the librarians as the “pick and deliver” room. Eight of these workstations exist on either end of the pick and deliver room, while the ninth and central workstation services the library’s center aisle.

Whereas the eight outer aisles are suitable for standard print material, Mansueto’s central aisle was designed for “special collections.” I was able to see massive racks with 2,500-pound limits. Some were filled with Mansueto’s audio recordings, records, elephant folios, and archival material. These unusual materials required a system different from the other aisles. Combining the two approaches makes this library distinctive compared with other library automated systems.

The total capacity of Mansueto is estimated to be 3.5 million books, making it one of the largest ASRS-equipped libraries in North America, as well as the only such library system to be completely underground. Mansueto’s cranes take an average of roughly three minutes to retrieve a book after it has been requested. The goal then, was to implement a system that allows anyone inside of the Regenstein Library to order a book from the depths of Mansueto and have it ready by the time they crossed the bridge and walked through its doors. Today, over a decade since Mansueto’s initial opening, the average retrieval time of three minutes is still being met.

This is likely in part thanks to the simplicity of Mansueto’s design. The workstations and the crane bed–where bins are loaded onto the crane–are made with simple twin chain drives. The crane uses a simple “steel finger,” as Bottorff described, to slide into the bin’s metal handles and move the bins as appropriate. The simplicity of the system is one major reason why problems and breakdowns are so rare at Mansueto.

But, being a library that contains countless numbers of precious texts, Mansueto also prizes safety alongside speed. The automated cranes are tried and true, as they are identical to those widely used in fast-paced warehouses. The library also deliberately slows down the cranes to an operating speed much slower than the standard speed. This is done because, unlike a warehouse that is likely indifferent to breaking a few parts in the name of speed, Mansueto Library would afford no such risk tolerance to destroying its texts. Library engineers were also careful when designing the crane’s transportation: each crane only moves on one track and is designed with extremely low tolerances. This means that if a crane was to detect that a single bin was jutting out a few millimeters more than expected, it would refuse to pass by the container out of an abundance of caution for the crane’s mechanics and for the contents of the offending bin. In these circumstances, a delicate human touch is employed as a library staff member gets behind a computer and manually nudges the bin back in place using the behemoth crane.

Future storage considerations

With the Library system above capacity for storing print materials, librarians are preparing to begin using a commercial off-site facility to store the low-use print serials currently housed in Mansueto. When materials are moved off-site, faculty, students, and staff will be able to request scans of articles or get physical volumes through links in the Library Catalog. Scans will take approximately one business day; physical delivery will take a few business days. Librarians estimate they will begin to relocate items to off-site storage during Autumn Quarter.

In the long-term, the costs for the commercial off-site storage facility will grow substantially as more material is added. To ensure that sufficient funds remain available to keep expanding the collection in support of research and learning, the Library is exploring additional options. This will include identifying whether low-use items in the collection that are readily available elsewhere could be withdrawn in consultation with faculty and assessing the feasibility of a new high-density storage facility for the University of Chicago.