I don't know how correct it is, but I remember being told in school that you don't capitalise the 'unimportant' words - the, and, by etc.
So, if you title is 'Harry and Sally' then that's how it's written, likewise, if it's 'Common Parasites in Non-ruminants'
Titles are weird. But yeah, i'd say lower case, but I'd also say to not worry too much about a cover page.
I've always been told that it's something you should put on every page of your manuscript in your header . . Correct??
Up top in your header: The Raging Sea by Joseph Anderson.
So based on that, I would think the issue is applicable to e-mail as well as snail mail. Or am I missing the boat somewhere here?
In my header I put: Book Title/My name/ page number
It's what I was taught eons ago, and it's practical and functional.