How long does it take you to write a book?

The time can vary a lot from book to book and I don’t always have the full story line resolved before I start. If I think I’ve got a good idea, I get started as soon as I can because when I start writing things down I soon discover whether or not the idea was really that good. Usually it takes me three to six months to get a picture book to the stage where I’m happy to send it to a publisher.