Like the other title in the "Extreme Earth" series, this book about lakes focuses on the biggest, the longest, the most beautiful, and the most unusual lakes in the world. It is primarily a geology book, so the author looks at the formation of the lakes, be it from glaciers, shifting rivers, or changing oceans. However, this is also an ecology book so Hanson addresses the current environmental health of the lakes and their future prognosis. For the Aral Sea she writes: "If the Caspian Sea (the subject of chapter 1) sounds like an oddly unattractive and environmentally degraded place, the Aral Sea could announce itself as actually horrifying." With black- and-white and color photos, as well as maps of the areas and illustrations of the geographic forces, Hanson looks at the Caspian Sea, Middle East; Aral Sea, Western Asia; Lake Superior, North America; Lake Baikal, Central Asia; Lake Titicaca, Western South America; and more. This is a reference book, or a read alone book for the very motivated. Hanson does not repeat herself from chapter to chapter but rather offers references to the appropriate chapter for further discussion. It is, however, a dense book and not an easy read. But for students who are motivated, Hanson offers a great deal of good information. Back matter includes an extensive listing of books, magazines, and web sites to get more information, as well as a glossary and an index.