As educational and research needs have changed, libraries have changed as well. They must meet ever-increasing demand for access to online media, subscriptions to archives, video, audio, and other content. The way a user/patron accesses this information has also changed. Gone are the days of a few hardwired desktops or computer carts. While libraries still need to support people without computers, many users bring their own wireless laptops, Netbooks, Tablet PCs, E-book readers, or smartphones. Whether using these for school studies, teaching, researching, or pleasure, users want to access information without switching between two computers. To alleviate the expense, headaches, and administration of wired connections, libraries have turned to Wireless Local Area Networks (WLAN) for primary network access. Going wireless eliminates the need to have fixed location PCs, the headaches of too few wired ports, and troubleshooting broken cables. By switching to WLAN, the library evolves to a "learning commons"--creating a collaborative learning environment and providing users easy access. The learning commons creates a flexible environment where individuals, small groups, and large groups can collaborate, accessing information simultaneously with any wireless device while sharing ideas and problem solving. A learning commons encompasses both in-building and the surrounding campus, extending the library beyond the four walls to courtyards and other areas around the library. Users can connect and research wherever they are. The library's WLAN becomes a critical service delivery medium for users and guests. A wireless network that fails to provide secure, predictable, and reliable access will frustrate users and library staff. The WLAN must provide strong authentication for controlled network access, high quality service to support various media types and devices, and be capable of scaling to dense user environments with hundreds of users at any one time. In this article, the author discusses five primary WLAN requirements for 21st century libraries.