How to extract a .VOB file from a disc?

I recently recorded several episodes from a TV series onto blank DVD-R discs. I am trying to extract them efficiently from the discs and onto my computer, but it is proving more problematic than expected. The files on disc show as .VOBs, and some of the files show only parts of one episode, while others contain parts of 2 episodes together, but not complete. I have tried editing these files, converting them to a more workable format (.avil .mpg, etc), yet I cannot work out how to fully extract the episodes in their entirety and without such errors. How would I go about doing this? Is there a specific software that would facilitate this?