Yes. When you first connect iPod to your Mac, iPod recognizes that Mac as its "home" computer. Each time you connect, iPod automatically downloads the music library stored on it. When you connect iPod to a different Mac, iPod asks for permission before updating, or synchronizing, with this music library. If you choose automatic update, your iPod recognizes the second Mac as its home computer, and breaks the link with the original Mac. If you do not choose automatic update, iPod switches to manual update mode, allowing you to selectively drag songs, albums, or playlists from the second computer to your iPod. Synchronization occurs only in one direction, from your Mac to your iPod. This means you cannot transfer music, automatically or manually, from your iPod to a computer, and you cannot use iPod to copy a music library from one computer to another.