Degrees of Belief: Subjective Probability and Engineering Judgment artfully weaves together three elements at the very core of engineering: uncertainties in knowledge; inductive reasoning; and individual expertise. Written from a geotechnical and earth sciences perspective, it brings new meaning to these concepts for nearly any field of engineering, science, or technology decision making. It begins by examining the tension between theory and practice, showing how this is manifested in the different meanings of probability used in reliability and risk analysis. This book emphasizes the cognitive processes used in conceptualizing uncertainty, with techniques and tools for subjective probability assessment. Turning to what this requires, it lends substance to professional judgment by examining its diagnostic, inductive, and interpretive elements. It also investigates the nature of expertise by bringing to life such towering figures as Roebling, Stevens, and Terzaghi, and their monumental engineering achievements. Masterfully synthesizing a wide variety of sources in a way directly relevant to engineers, the book draws on the history and philosophy of science through the work of Thomas Kuhn and Henri Poincaré. It provides a window on current behavioral research that applies it to everyday thinking. This is all richly illustrated by examples from practice, including a gripping reassessment of the 1986 Challenger incident as seen through the eyes of the engineers who experienced it. From philosophical foundations to nuts and bolts, this is a groundbreaking book of serious content and sparkling style sure to engage any engineer or scientist who thinks about what they do and how they do it.