iTunes and Ripping Music

Ok here is the situation. My family has a rather extensive music collection mainly in the form of CDs. We want to compile a digital library of all of our music that can be shared over the family home network. Currently we are all using macs so you think that you could just rip everything into iTunes and voila.

However, I have, on a couple of occasions now, been close to completing this task when I have gone to update my current itunes and all the data has been earased from the library. I still have all the wave files that I have encoded on my harddrive, but when I go to load them back into iTunes, none of the information (song title, artist, album title, etc) is left. It just brings in the audio files without any data to identify them.

What do I do to prevent this from happening again?

Thanks

**doffs her cap and vanishes**