Is it ever a good idea to self-publish?

Is it ever a good idea to self-publish?

Derek Johns (Managing Director - AP Watt Literary Agency) gives expert video advice on: Should I consider using a vanity press?; Are there any good alternatives to traditional publishing routes?; Can an agent help me publish my work via non-traditional routes? and more...

There are a number of instances of self published books that go on and are taken up by large publishing houses. They tend to be non-fiction books with particular local interest in the first place. It's very difficult if you print your own book, it's very difficult then to go on and sell it. You can go round to the book shops, but then you may find their not particularly interested in taking it on.