At first, Jeanne Heifetz thought she had merely tripped over one of those quirks that occasionally worm their way into standardized tests. Words were missing from a book excerpt she was familiar with on a Regents English exam. But when she discovered a second extensively altered excerpt, she began to wonder, "If there were two, could there be more?" Was something sinister afoot? So, driven by curiosity and her antipathy to the exams, she rounded up a batch of recent Regents tests, which New York State requires public high school students to take to graduate, and started double-checking the excerpts...