Working Backwards

I was getting caught up it little details of the story this week, and it made my brain hurt!  Although I am slowly chugging along, I decided that I wanted the end of the novel to be my driving force for the storyline.  Today I decided to go ahead and write the final scene of the book.  It's very short, so I will have to add to the beginning of it, but I am, overall, very satisfied.  I have also written down a few scenarios that I know need to be included in the book.  I think I may try to write them in their entirety, and fill in the gaps.  I don't think this is common novel writing practice, but I'm new at this, so I'm making up the rules as I go.  It may pan out; it may not.  I'll let you know.