Your secret desire

Many of us who love to read also enjoy writing. Some of us are published authors while others daydream of being published...and successful...and able to write full time, slamming the door behind us as we leave our current day jobs. So, if you had absolute knowledge that you would be succesful, what kind of book would you write? Don't trot out your standard answer that you give at parties and in letters. What is your secret desire for your book?