People want to communicate, and history shows that they always gravitate to technologies that make it easier to reach out to one another. The printing press, universal mail service, the telegraph, telephone, motion pictures, radio, television, and the Internet have all served people's need to communicate. And the easier it is to communicate, the more communication occurs, as a quick glance at your email might tell you.

The general rise of communication technologies has made the world smaller, and the Internet in particular has made it practical for people who may never have otherwise met to work together. This book is a great example: two of the authors (Tom and Dori) live in northern California; Wei Meng lives in Singapore; and Brian, our editor, lives in Rhode Island.

The Internet is so useful, in fact, that many people think of Net access as a necessity, rather than a luxury. And when something is a necessity for your work or play, you want it available, well, everywhere, or at least everywhere you go with a laptop computer.

That's where wireless networking comes into the picture. Mac users can connect to the Net whenever their iBook or PowerBook is in range of a Wi-Fi network. That could be at home, at school, at conferences, or even in public hotspots such as an airport, a local Starbucks, or Borders Books and Music. Or, with a laptop and a Bluetooth phone, you don't even need the Wi-Fi network.

Wireless technologies in Mac OS X aren't just for Internet access, however. You can also use your Mac to communicate wirelessly with peripherals such as mice and keyboards, to connect to your cell phone or PDA, or to share files and use iChat with other computers.