Recognize that there are three 'names' relevant to any discussion of Thunderbird address books: 1) the name of a file which holds address-book contact data; 2) the name by which the address book is referenced within the Thunderbird user interface; and 3) the name of a descriptor by means of which the address book is referenced and parameterized in 'prefs.js'.

The foregoing can be most easily appreciated by using Thunderbird's configuration editor [Tools | Options | Advanced | Config Editor...] to 'Search' for 'ldap_2.servers' then sorting by 'Preference Name'. The filtered results will, for each address book, display a short list of associated parameters of the form 'ldap_2.servers.<descriptor>.<parameter>'.

Absent any user (re)configuration there are two address-book descriptors: 'history' and 'pab'. [There may appear, also, to be an address-book descriptor named 'default' but this set of parameters serves a tangential function irrelevant to this issue.]

Note that, for each address book, the associated descriptor names the associated file via the 'filename' parameter and the associated UI reference via the 'description' parameter.

Note, also, that all of these parameters can be modified which, presumably answers your question.

All that having been shared, I cannot resist recommending that one not re-parameterize the 'history' and 'pab' descriptors due to the fact that Thunderbird code affords them somewhat special treatment. I have no interest in the special treatment afforded the address book parameterized via the 'history' descriptor so I simply disable it [Tools | Options | Composition | Addressing | Automatically add outgoing e-mail addresses to ...] and let it remain empty. As to the address book parameterized via the 'pab' descriptor, I find that it provides a convenient place to temporarily save the address of a new correspondent [by selecting 'Add to Address Book' from the context menu spawned by clicking on the 'From' address of his incoming eMail] pending a fleshing out of additional fields associated with the new contact and a relocation of the thereby completed contact record to one of my working address books (eg. 'Family', 'Friends', 'Associates', 'Vendors', etc.). Food for thought.

I appreciate MCVenner's prompt and erudite response to my question. I followed the guide and - accepting the small changes I list below - located the 'Values' that may be altered to change the Address Book Contacts Folder names. This was the route I followed:

Select: Tools | Options (ignore the 5 alternatives) | type 'Advanced' into 'Search' to filter the options | select 'Config Editor' (and confirm "I accept the risk") | type "ldap_2.servers" into 'Search' to filter the results | find the 3 String Values: 'Personal Address Book', 'Collected Addresses' and 'Contacts'. Right click and select 'Modify' to alter these 3 Address Folder titles if required.

The 3 strings identified (in my case ) are: ldap_2.servers.pab.description;Personal Address Book ldap_2.servers.history.description;Collected Addresses ldap_2.servers.Contacts.description;Contacts

Acknowledging MCVenner's caution about altering these values, are there any others who have done so without harm and would like to add their comments before I make any decisions?

I have three 'Address Book' Folders and wish to rename them more appropriately. The first one is entitled "Personal Address Book" and cannot be altered in 'Right Click - Properties' '. The other two however, (names "Contacts" and 'Collected Addresses") can be altered it appears. Is the primary folder a fixed default or is there a way to rename this one too?

It is a fixed default at this time. While it may be possible to specify another name by changing hidden preferences, there is a high probability of the change causing an issue as there are certain assumption developers and addon authors make that might see you have issues changing setting that have no user interface. Perhaps from something as simply as a future upgrade using your chosen name for another type of address book so things go pear shaped.