in reply to Implementing a Mixin Class

I have been teaching myself OO Perl (with no prior OO experience of any kind) and while I think I understand what the 'mixin' problem might be based on problems I've encountered trying to build complex sets of intertwined classes, but this is the first time I've seen this term used.

Since I don't see this term elsewhere in a PerlMonks search and it doesn't appear in the index of any of my dozen perl books, could someone provide a clear explanation and description of 'mixins'? What they are, what they're intended to solve and so on?

I would greatly appreciate this.