The Irish Potato Famine would seem to be an unlikely topic for a children's book, but this juvenile history is accomplished, engaging and admirably forthright. Susan Campbell Bartoletti focuses on the people -- particularly the children -- many of whom starved in record numbers during five years in Ireland in the 19th century. The book is handsomely illustrated with black-and-white period engravings, but it's not a picture book. Amateur historians (ages 9 to 12) will appreciate its thoughtful, challenging approach to the topic.  (IRE101, $18.00)