Did you know that Yellowstone National Park has more geysers and hot springs than anywhere else on Earth? The geyser called Old Faithful shoots boiling water 130 feet (40 meters) into the air! But what causes geysers to erupt? And what other wonders can be found in this beautiful national park? Read this book to find out! Janet Piehl lives in Evanston, Illinois, and is a children's librarian. She grew up in Shorewood, Wisconsin, and attended Macalester College. Janet has lived, among other places, in the Twin Cities and France. She got her start as a writer working in the editorial department of Lerner. Janet liked the research aspect of writing and editing so much that she became a librarian. Now she helps kids find and use books just like the ones she writes!