aha ! now i understand !! i have been modifying a lot of meta-data in my library so that is where all those .save files came from. i was confused because i usually transferred the book to my reader after editing the data. if i had an .imp book which was lost / corrupted, if i just remove the .save extension, the .save file becomes an .imp file again with no other intervention necessary ? good to know (although i doubt i will need this).
i don't see any corruption coming from these minor details so i think i can safely get rid of the .save files. maybe i will stop playing with the meta-data so much to avoid them...
i don't use the Librarian to create .imp files (i tried, but it didn't work very well), only to transfer them to my device. i use ebook Publisher to create them.
thanks very much for the info ! i knew someone would know the answer here !! you guys are brilliant !