This document provides an overview of wireless networks. It begins by defining a wireless local area network (WLAN) and how it connects users wirelessly within a building while using a wired backbone. Common topologies include connecting the wireless LAN to the wired LAN through an access point, or using a completely wireless network without centralized control. The document then discusses how wireless LANs operate similarly to wired LANs using the same protocols, how they integrate into existing networks through access points, and their unique physical/data link layers, security considerations, interoperability requirements, and performance differences.