Book excerpt: Robert H. Dott, Jr. and John W. Attig wrote Roadside Geology of Wisconsin to help residents and visitors alike envision mastodons roaming in front of glaciers 12,000 years ago, feel storm waves pounding sea cliffs 500 million years ago, and hear volcanoes exploding 1,900 million years ago. With lively prose, detailed maps, black-and-white photographs, and shaded-relief images, the authors succeed in their goal, unraveling the 2,800 million years of geologic history recorded in Wisconsin's rocks. Introductory sections describe the geology of each region, and thirty-five road guides locate and interpret the rocks, sediments, and landforms visible from the state's highways, including the Great River Road in the Mississippi Valley. Roadside Geology of Wisconsin delves further into the geologic history of specific sites such as Apostle Islands National Lakeshore, the Wisconsin Dells, the geologically renowned Baraboo Hills, and more than twenty-five state parks. Features of and access points to the Ice Age National Scenic Trail are noted.