They are "alien" because they come from somewhere else; they are "invaders because they are taking over." In a clear, informal text, illustrated with handsome color paintings, this intriguing science book discusses particular plants , animals, bacteria, and viruses that humans have, deliberately or accidentally, introduced to a new habitat. The focus is on aliens that destroy their new habitats and threaten extinction of native plants or animals. Many readers will be caught by the dramatic disasters: "The sea lamprey, a slithery vampire, sucks blood, then tissue, then bone from fish in the Great Lakes"; if Asian long-horned beetles were to escape into a North American forest, millions of trees would die; the roots of the purple loosestrife flower grow so quickly they suffocate surrounding vegetation. A final chapter addresses how young environmental activists can help, but interested kids will need to go elsewhere to find contact information that will get them going. A bibliography would have been useful.

Gr 3-6 The authors introduce three classic examples of alien invaders: brown rats, cane toads in Australia, and the fungus that caused the potato blight in the U.S. and Ireland. Ten more species are introduced with a narrative that describes the invader, its life cycle, the damage it causes, and attempts to control it. A short list of facts gives the common and Latin name, the size (metric and English), homeland, invaded countries, and the method of entry. Additional chapters describe some vulnerable habitats such as Lake Victoria, the Great Lakes, Hawaii, the Eastern hardwood forests, and the Western rangelands. The chapter "Get Ready for the Pandemic" explains why the avian flu virus (H5N1) has the potential to be catastrophic. The concluding chapters give further perspective on the impact of these species and what people are doing and can do to control them. The background on each double-page chapter is a full-bleed color painting that includes an illustration of the invader. A world map shows the origins and destinations of a few of the threatening species. Other than a confusing chapter on "The Role of the Community Elder," the material is accessible and will be useful for young researchers. Carol S. Surges, McKinley Elementary School, Wauwatosa, WI