Scientific uncertainty puzzles many people. The confusion arises when scientists have more than one answer, and disagree among themselves. By acquainting readers with the ways that uncertainty arises in science, how scientists accommodate and make use of uncertainty, and how they reach conclusions in the face of uncertainty, this book enables them to confidently evaluate uncertainty from their own perspectives, in terms of their experiences. Henry N. Pollack is a professor of Geology in the Department of Geological Sciences at the University of Michigan. He has published extensively in the field of geophysics. This is his first popular science book.