The latest marketing ploy for cookbook authors is pop-up stores for their books and food samples offered through portable trucks (like pushcarts). Martha Stewart has recently been touting her tarts this way. Anyone willing to shell out $27.00 for her book receives a free tart and a raffle ticket for tickets to her show. Dorie Greenspan, a wonderful baking expert and author, has been offering treats via her Cookie Bar. If you see your favorite food writer on Michigan Ave. soon handing out samples, don’t be surprised!