SIX MONTHS ON THE KINDLE BESTSELLERS LISTS!   Not so long ago, in the tiny, isolated villages of Finland, where prolonged summer days gave way to endless winter nights, people would pass the time by singing the many adventures of their favorite heroes: the mighty, magical men and women of ancient days.   They sang of old Vainamoinen, greatest of sages and magicians, who helped create the world but never could find a woman to wed him. They sang of his friend and ally Ilmarinen, first among craftsmen, the blacksmith who forged the dome of the heavens.   They sang of Louhi, the ancient lady of Northland, whose crafty wit and magical powers made her a worthy opponent for Vainamoinen himself. And they sang of Aila, Louhi's lovely daughter, who captured the hopes of the two old friends and drew them as rivals to the shores of Northland.   And while these songs could still be heard, there came along a rural doctor, a scholar, who gathered and wove them together in a book he called the Kalevala. And so he created for Finns a national epic, and for the rest of the world, a work of wonder.   The songs endure, the heroes live. . . .   For ages 10 and up. Not illustrated!   /////////////////////////////////////////////////   Aaron Shepard is the award-winning author of "The Mountain of Marvels," "The Magic Flyswatter," "The Monkey King," and many more children's books from publishers large and small. His stories have also appeared often in Cricket magazine.   /////////////////////////////////////////////////   SAMPLE   Vainamoinen chanted and Joukahainen sank in the marshy ground, up to his waist in the swallowing earth.   Cried Joukahainen, "Reverse your words, undo your spells! I will give you a hat full of silver, a helmet full of gold."   "Keep your wealth," said Vainamoinen. "My coffers overflow." He chanted again, and Joukahainen sank to his chest.   "Reverse your words, undo your spells! I will give you fields for plowing, meadows for pasture."   "Keep your land. My farm stretches beyond sight." He chanted again, and Joukahainen sank to his chin.   "Reverse your words, undo your spells! I will tell you of the fairest woman, the finest maiden."   Vainamoinen stopped his chant.