If you're going to edit a film or music video or any kind of media like that THIS IS THE ONLY BOOK YOU NEED TO READ. I don't make that statement lightly. Murch's book is without a doubt the best book I've read on the theory, thought-process and intention behind WHY an editor makes an edit. There are a multitude of boring books (I know because I bought many of them) on editing and why you should do this and that. Whatever. Murch has won loads of awards for his work and even directed a feature himself (Return to Oz) so he knows a much about the filmmaking process.
This book will not be helpful during the edit of your footage. You will not be able to turn to page nineteen and find out when to use a jump-cut to best effect. What this book helped me to see was the approach you need to have towards the editing process as a whole. Maybe not even just as an editor but as a filmmaker and story-teller too.
I can't stress enough how useful reading this book was to me. I used to be very frightened of getting into the edit but when I read this I found a new way of looking at my footage and became able to accept that things are different. Murch's writing style is very informal and as a result I think that the book requires a few reads (at least I've read it three times now and I get a better understanding of his ideologies each time).
Forget all the other rubbish people charge through the nose for. All you need to teach yourself editing is the software, footage and this book.