Sometimes there is no carrier. Single Sideband for example. Of course most of the newer modulation schemes are at base a form of FM or phase modulation, in a sense they are nothing but a carrier, but of course in reality their energy is spread over an even larger bandwidth than the information bandwidth, although hopefully not much wider. That's in part why FM stations are spread farther apart than AM ones. Of course they also have a higher baseband (the music/audio) bandwidth, but their modulation side lobes extend out proportionally farther as well.
Take a look back over my post.
(I talk a little about spread spectrum) :-)