How do CDs work?

It amazes me when I think about how we have come in technology. One advancement that was always impressive to me was cd's. It amazes me how they can fit so much information on such a small disc. Unlike the vinyal records, compact discs use a laser to read the disc. The laser reflects off the disc and is sent back to the eye which read different bumps in the disc. The cd player then converts the bumps into sound waves and out your speakers. In the field of music we came from vinyal to eight tracks to cassettes and then to compact discs; what will they think of next?