The Art of the Flask: Entertaining from the Hip by Paul Knorr. ISBN: 978-1-60433-698-6. Copyright 2017. Hardcover with 207 pages including index. Celebrate the history and convenience of the flask; a classic drinking vessel and the ultimate secret fashion accessory for a man or a woman. Flask etiquette, cocktail recipes, flask care and cleaning, finding the right flask, and famous flasks are included in this full-color, flask sized book.