I was fascinated as a 4th grader, in 1942, that the year was an anagram of the year when "heroic" Columbus and his cohorts sailed into this hemisphere. I've changed quite a bit in five-plus decades, and so has my view of the man and his cohorts-the books of my childhood made no mention of the Spaniards' callous treatment of the natives. As you prepare to teach about the explorers' impact on world history, make certain your youngsters receive a balanced perspective. In addition to other more favorable books, you'll profit by perusing Hans Koning's polemic, Columbus: His Enterprise. The real Columbus existed somewhere between the unblemished hero of my youth and Mr. Koning's archvillain.