They guys from CD Freaks.com have written a nice article that explains the upcoming audio CD replacement, the SuperAudio CD (SACD). This new technology developed by Philips and Sony has an increasing popularity.
You can read the entire article here at >> cdfreaks.com and it contains both technical details as information that should be understandable for the general public. Be sure to check it out, so you are up to date and know what to buy if you are looking for a new hifi or home entertainment set!