Subtle this book is not. The Paper Bag Christmas by Kevin Alan Milne is the story of two kids whose parents sign them up to volunteer as Santa’s elves at the local children’s cancer ward, where they meet a parade of caricatures: a tough-tawkin’ janitor from ”da Bronx,” an excessively polite young Indian patient, and a jolly doctor named (say it fast) Christoffer K. Ringle, who might be the real ?St. Nick. Still, if you can get past the ham-fisted schmaltziness of it all, there is a sweet, if not exactly innovative, tale here about the true spirit of Christmas. B?