”Over the course of nine innings hundreds of silent signs and signals are given and received by managers, coaches and players…” So begins Paul Dickson’s new book, The Hidden Language of Baseball (Walker Books, $22.00). Hidden serves as a history of this fascinating, though often misunderstood, part of baseball. Prospectus correspondent Peter Schilling Jr. discussed with Mr. Dickson the nature of signs and sign stealing in baseball today, as well as the controversy surrounding Bobby Thomson’s ”Shot Heard ‘Round the World.”