The link that Michael has provided gives the answer regarding using match as a backup. However, I would add a couple of points.
Firstly, you should not be losing songs from iTunes for no good reason. You are either doing something that is inadvertantly causing songs to be deleted, or there is something wrong with iTunes.
Secondly, whilst you should always keep a backup of your entire system, you may well find that match will provide a quicker solution if your files do delete for any reason, bearing in mind any issues identified in the link about incorrect versions etc. I would also point out that whatever it is that causes your songs to delete from iTunes may well also delete them from the cloud.
Thank you both.
I probably lossed them in a computer upgrade, they were not played often. At the time I was given instructions from Apple that to backup iTunes you had to follow rigid steps and actually make a backup copy by moving files via iTunes to one location...external drive...and then move them back, leaving the first there. It made no sense to me.
Now I find all my songs are on my backup, except those I've lost, nicely sitting in the Music Folder as they should be.
I'll probably never know what happened. But I am thankful to know iMatch's limitations.