RAR files are multiple copies of same thing???

I notice that all the games I have d 'ld have like 20-30 rar files that are exactly the same size (19.531K) and then one rar file that is (1,464K) for example. When I decompress the large rar it is the first track ISO...so why is there so many of them?? and where are the audio files?

Radiant Silvergun was straightforward...but all other games are leaving me with ? over my head...

Please Please someone help clear up the file structures for me...cause I am able to use cuesheets/burn and so forth...
with the RAR format.... you can split up a large file into multiple files when compressing....this way you don't have to download a huge 400MB at once... this makes it easier because if one of the RAR file get corrupted... you don't have to download the whole file.... just that one RAR file... much easier.....now the thing with the audio.... your problt use to those ISO/MP3 releases.... well thess big games store the audio tracks inside the big huge BIN file