Thank you dl_bridges, but I have already read both of the pages you point to, as well as your own thread, and the KDE one (http://forum.kde.org/viewtopic.php?f=20&t=86058&start=10#p150136
) where the forum manager, after speaking to KDE developers, reveals Kaddressbook won't be ready for production use until version 4.5.
What you suggest appears to work until I start adding new entries to the address books. Then it all goes haywire with some entries (mostly the new ones) turning up in kaddressbook and others turning up in KMail, but none being visible everywhere. One address book became mysteriously empty, and another had only the new entry in it, with the other 40 invisible. This is why it's taken me about three weeks to discover the problem, because initially Akonadi just imported my address books and they seemed to be working.
I'm worried that if I continue to use the current version my data will get scrambled until it will be impossible to work out which contact belongs where and my business and social life will be irreparably ruined. I rely on ten separate address books, so the software has to be dependable. I won't be able to sort it out if it gets muddled up.
That is why I would like pclos to revert to a reliable version until KDE have finished experimenting. People's data is too valuable to risk in this way.