The carol about ``Good King Wenceslas'' is expanded into a sentimental story in which a rather thoughtless young page is taken along to see how the less fortunate live; the bounty he and his king take to the humble cottage is shared in a sumptuous feast after the king himself builds up the fire. The telling is adequate if prosaic; it does serve to explicate John Mason Neale's verse, which younger children may find obscure. Englander's attractive illustrations set the story appropriately in medieval Eastern Europe; the page (also named Stephen—it's his birthday as well as the saint's day) looks like an appealing blond member of a modern third grade, while the grandly clothed king is thoughtful and suitably benign. Not essential, but enjoyable. (Picture book. 4-8)