See gbcdoj's reply in Post #210.
Apostolic succession relates to the ordination of bishops and priests through the sacrament of Holy Orders--what you know as "laying on of hands"--which we believe is not merely a symbolic gesture but confers actual, and permanent graces (see 2 Tim 6:"For this reason, I remind you to rekindle the grace of God that is within you with the laying on of hands", also 1 Tim 4:14). Protestant denominations, for example, had their succession broken at the time of the Reformation because they did not recognize Holy Orders as a sacrament that gives grace, and so could not confer that grace on their ministers. However, other Christians not currently in union with Rome (Eastern Orthodox, non-Chalcedonians) are recognized to have kept their succession intact because they kept the rite of Ordination intact as a Sacrament and they continue to do so even today.
Succession isn't magically transferred to one pope after another, nor is it restricted to the Pope alone. It was passed down from the Apostles who "laid their hands on" bishops, who laid their hands on other bishops and so on. The idea is that the current Pope, if you go back far enough, was ordained by someone who was ordained by someone all the way back to an Apostle. It's not necessary that JPII be ordained by JPI or any previous Pope, for that link to be maintained.
All bishops are basically in the line of Apostolic Succession. The bit about the "unbroken" line of Popes means (I think--I'd have to see the context) that the office of Bishop of Rome can be traced all the way back from A.D. 2005 to its establishment by St. Peter.
I have no problem with the definition of "Apostolic Succession", though I don't agree it is necessary or that it is shown from Scripture to be a requirement. But that's another story. :-)
Well, yes there is a published list of "Popes" and "Anti-Popes" going all the way back to Peter. It is this list which I believe is imaginative if nothing else.