If I'm submitting a partial manuscript, do I need to know the ending?

If I'm submitting a partial manuscript, do I need to know the ending?

Derek Johns (Managing Director - AP Watt Literary Agency) gives expert video advice on: How long does it take to go from finding an agent to getting published?; What happens when a book is accepted for publication?; What should I do if a publisher asks me to make revisions before they accept my submission? and more...

When you're submitting a partial manucscript you have to have a synopsis. That doesn't mean to say, of course, the book need necessarily go in the way intend. Novels are organic things. They have a habit of going off in unexpected directions, but everybody understands that.