Book World Services in Sarasota, Fla., introduced what president Ronald Ted Smith calls his "cash contributions" program, aka co-op. It's the first time the company has ever offered co-op, and it started with $1.50 per book on all titles with suggested retail prices of $30 on up. There is no dollar cap. The idea of offering co-op started with Smith's effort to insure that its new coffee-table book, The Age of Flight: The History of America's Pioneering Airline by William Garvey and David Fisher, published by Pace, takes off better than its troubled subject, United Airlines. "It's a gorgeous book," said Smith, who is himself a pilot. "By the end of the 2001, we laid down nearly 40,000 copies."