I have recently discovered te Catalogue function of Calibre: what it does is to create a file (epub in my case) which lists all the books and organises them based on various tags - I attach an example (these files are in a directory "trialcatalogue" on my laptop, as a subdirectory of "calibre" that is thsu listed as teh "author" of this epub).
At the moment there is a bug so that for the new models (well, surely for PB903) you cannot create the catalogue while your device is connected to the pc, but you can send this file to the device.
It is rather neat, but of course the great thing would be if one could click on the name of the desired book-document and actually open it in the device. I asked if there was a way to do so in the Calibre forum, but apparently doing such a thing is device dependent. I have no idea of how to do it
but I thought I should relay the problem here in case somebody has already solved it!