Quote Originally Posted by Cumulus View Post
Well, if you translate it into English, it would be: "Were you reading War & Peace?"

I agree with Yulia - A simple ДА would sound as if the person would've agreed that the book had been used to read a few lines or two, but not necessarily everything.

Прочитать, on the other hand, would emphasize the outcome (=reading the whole book)
This is not correct. It would normally be translated as "have you read War and Peace" or "did you read War and Peace"? It's true that it could mean "were you reading War and Peace" but only in a rather specific context (i.e., "were you in the process of reading it when something else happened?").

It's true that я читал Войну и Мир does not necessarily imply that you completed reading it, in the way that я прочитал would. But in most contexts I think this would be implied.

Similiarly in English -
"Have you read War and Peace?"
If you had only read parts of it you would probably answer, "Yes, but only parts." If you just answered "yes" people would probably assume that you read the whole book. It's the same in Russian.