Burn To The Brim is a utility which selects the group of files or directories (documents, mp3 files, whatever you like to burn) which optimally fills a CDR or other medium (or multiple CDRs/media).
The program analyses the files and folders in a folder you specify, and groups them in the best possible way. Most likely BTTB will find a near-perfect solution for you within one second, and a perfect one in just a couple more.
The first priority is to fill the media to the brim, second is to minimize the number of items (so the larger, harder to fit items have preference and more items to choose from are left for the next burn).
BTTB is optimized for quick performance and considers the most promising options first. It also intelligently minimizes the search length by fast detection of dead ends.