yep - mobi2mobi works great on azw files. An example for what you're suggesting would be: mobi2mobi currentfilename.azw --outfile same file name if you wish(just be sure and put file names in "" if they contain spaces) --title "ref book title". Your mobi2mobi.exe file should be in the same directory as the books you want to rename unless you add a path for mobi to your system file. The only nice thing about using numerics in the title is that they sort first. I use 1 for library books and 2 for Kindle store books, 3 for free books, 4 mobileread books, etc. Then I can use alt+numeric to go to the beginning of that section.