Best method to edit body of .prc/.mobi files?

[Skydog]

I've searched on the forums and read FAQs which have not answered my question (or it's quite possible I am clueless).

What is the best way to go about editing the body of my .prc/.mobi files? For example, I have many older ebooks that have no breaks between paragraphs and no indentations. Quite annoying to read this way. I only know how to perform simple edits of metadata with mobi2mobi, but nothing major that is required to affect the entire text.

I am familiar with the necessity to edit html code for epubs, but have no experience with it or style sheets. I suspect something similar will be necessary for my mobi files. Will manually editing every paragraph in the book be required?

Can someone provide a link or two where I might be able to read what exactly I will need to learn in order to edit the files properly?

Thank you for your assistance.