What's in a name?

I've been musing on the subject of book titles, and how much they contribute to a novel's success. Some titles seem to be very important. 'A Brief History of Tractors in Ukranian', and 'Salmon Fishing in the Yemen', for a start. I have read both these books, and quite - only quite - enjoyed them, but it was the titles which attracted me almost as much as the hype. Would they have done as well as they have done if they'd had less interesting titles? It's hard to know. Some books have done very well with uninspiring titles - 'War and Peace' isn't exactly attention-grabbing; neither, come to think of it, is 'Emma'. But obviously publishers do give a lot of attention to titles. I wasn't allowed to have my chosen title for my second novel, and I gather David Isaak wasn't allowed his, either (what was that title, David?). I suppose if you're very well-known, it doesn't much matter what your book is called ('Saturday'? 'The Sea'?). Having said all that, I love fun titles (The No.1 Ladies' Detective Agency is another), but maybe there isn't room for too many quirky titles. If quirky became commonplace, it wouldn't be quirky any more, and then I suppose titles like 'The Outcast' (a book which, incidentally, I loved) would be the new exciting.