How Come? Planet Earth (by Kathy Wollard)

This book and its predecessor, How Come?, were written by the author of a syndicated newspaper column that answers questions from kids around the world. Younger readers will relate to questions and answers about cats purring and dogs barking, but adults will be interested in entries on high blood pressure and cholesterol. In between is a wide range of factoids explaining why people burp, sweat, and bruise.

Many of the illustrations are unsophisticated groaners, but kids will like them. The book does better when it sticks to cut-and-dried explanations such as how dinosaurs are named or how many eyes a fly has. When it pokes into more complicated concepts, the book's answers lack necessary depth, may be dry and dense, and may leave readers with even more questions. Still, the book gets points for trying, and most entries will satisfy, if not sate, readers' curiosity.