The document discusses four main types of computer networks:
1) PAN (Personal Area Network) connects devices within about 10 meters and uses technologies like Bluetooth.
2) LAN (Local Area Network) connects devices within a local office or home using Ethernet or Wi-Fi.
3) MAN (Metropolitan Area Network) interconnects LANs within a city using high-speed connections.
4) WAN (Wide Area Network) extends over a large geographical distance, such as between cities, using leased telecommunication circuits and can include the Internet.