Some devices serve the purpose of connecting your Mac to networks or peripheral devices. In the case of networks, you use an Ethernet hub to enable your Mac to communicate with other computers, printers, network file servers, and the Internet. In the case of peripheral devices, you can use a USB or FireWire hub to expand the number of peripheral devices, such as printers, cameras, scanners, and so on, that you can connect to your Mac at the same time. Hubs are usually simple to install and configure (in fact, they often don't require much configuration at all).
One of the best ways to connect Macs to one another is through an AirPort Base Station, which acts as a network hub. You can also install AirPort Base Stations on wired networks, such as those connected through an Ethernet hub, and the station can "cross over" the data from the wired to the wireless network.
To learn how to install and configure an AirPort network, see Chapter 11, "Using an AirPort Network to Connect to the Internet," p. 297.