Urban public libraries in Atlanta and elsewhere have rarely been as popular — and rarely as besieged. Hard economic times have generated increased demand for the free and varied services libraries provide, as revenue-challenged local governments have cut contributions to library budgets. This comes as libraries are asked to perform new, changing functions.

Due partly to their role as default providers of computer and Internet access, today’s big-city libraries do much more than lend books and DVDs. They help residents find jobs, obtain health information and connect to government services and benefits. The Atlanta-Fulton Public Library System, for instance, has a consumer-health librarian on staff and provides a GED test preparation program.

Libraries are fulfilling what has been called their “shadow mandate,” supporting and complementing the work of other public and quasi-public agencies. City residents see libraries, particularly neighborhood branches, as multipurpose community centers, offering business assistance, tax help, public meeting spaces and places to learn English.

At Pew’s Philadelphia Research Initiative, we interviewed officials in 15 big cities for our study of urban library systems.

“People don’t know about the breadth and depth of library work — public health, urban gardening, diverse programming for all ages,” John F. Szabo, director of the Atlanta-Fulton Public Library, told us. “In some neighborhoods, libraries are the only safe space for kids.”

Atlanta-Fulton is a good example of what has been happening in a lot of urban library systems. Visits and circulation have risen dramatically, even though the library lost a lot of government funding. One reason is that library officials made it a priority to maintain branch hours, opting to reduce spending on programming and new materials instead. Even so, library usage in Atlanta-Fulton, measured on a per-capita basis, remains lower than in most other systems studied; the same is true for overall spending and the number of public-access computers. The system is slightly above average in terms of branches per capita.

Atlanta-Fulton’s experience is in keeping with another trend: When asked to spend on libraries, voters usually say “yes” in big numbers. In 2008, a $275 million bond issue for renovation and construction of library facilities passed in Fulton County with 65 percent of the vote. Voters in Columbus, Ohio, Los Angeles and Pittsburgh have overwhelmingly approved dedicated taxes for library operations.

As libraries struggle to keep up with changing demands in an era of limited resources, officials will have to make tough choices about which services to add and discard. They will have to be flexible, creative, and nimble, striking an ever-changing balance between old and new. It will not be easy.

Larry Eichel is project director of the Philadelphia Research Initiative at The Pew Charitable Trusts.