[Evolution] Address Book file structure

[Dave Smith]

Could someone explain the file structure for addressbooks please. I have
59 directories with variations on the name
1104155018.3809.27@localhost.localdomain plus one of System.

Each directory has tow files: addressbook.db and addressbook.db.summary.

I only have one addressbook (although I have had more in the past) but
never 58. So what are these directories and how can you tell what is
what when you need to import?

Thanks

Dave