It is basically a fluorescent light bulb with no wires to send electrical current into the tube itself. Instead, you coil a wire around the bulb and connect the coil to a ballast. The magnetic field created in the coil is what causes the bulb to do its fluorescent thing. There is another technology that sends a radio frequency signal into the bulb, but I think that is less commonly used. It is a bit tricky to do a Google or Bing search for induction lighting, without getting either Wikipedia (which I don't trust) or advertisements (which won't help you learn). But try searching for "how things work - induction lighting." Here is one result I found:
Charles E. Beck, P.E., Seattle
Comments based on 2008 NEC unless otherwise noted.