“While there is not a simple formula for determining whether a book has been profitable or not, a rough rule of thumb for calculating revenue is to take the cover price, divide it in half to reflect the retailer’s share, and multiply it by the number of units sold. To determine profit, costs such as overhead, printing, marketing and the advance must be deducted.” (“Betting Big on Literary Newcomers,” The Wall Street Journal, November 20, 2015, pg D2)