Decades of commercial whaling nearly decimated a variety of whales considered a keystone species. Keystone species are indicators of the overall health of Earth''s habitats. While whales have made a comeback through an international ban on commercial whaling, they are still threatened with extinction. Global warming, water and noise pollution, and commercial shipping and fishing are among the most serious threats to whale survival. Meet the scientists, citizen scientists, researchers, whale watching guides, and other concerned citizens who are working together to protect whale populations around the globe. Learn about whale biology, habitats, and behavior, and discover more about the high-technology tools that help researchers in their work.

Martha E. H. Rustad is the author of more than two hundred nonfiction children's books, on topics ranging from snowflakes to termites to the Statue of Liberty. She lives with her family in Brainerd, Minnesota.