Is there a way to comment on specific Document Version?

I have high hopes for document versioning. However, I can't find much information on the details. I'd like to understand how it works a little bit better. I have lots of questions. But the first thing that came to my attention is that to be really useful, I would need to make comments for a specific version. If I make a fundimental change in the document, I'd like to be able to make a comment about that version. Otherwise, I have to visually inspect the documents to see what version I need to restore. When working with very complex documents, it is very hard to visually inspect for that meaningful change.

Also, I would really like to read up on how versions work and documents behave. For instance, what is the significance of moving the file or copying the file. When does the versioning remain intact and when will it be left behind. I'd really appriciate if somebody could point me to any documentation or in depth review of the document versioning feature in Mountain Lion.

Thanks,