Introduction -- Formation of Flexible Linguistic Values and Their Mathematical Models ── Formation Principles and Modeling of Imprecise Information -- Fundamental Theories of Flexible Sets and Flexible Linguistic Values ── Mathematical Theories about Imprecise Information -- Truth-Degreed Logic and Flexible-Linguistic-Truth-Valued Logic ── Logic Theories about Imprecise Information -- Approximate Reasoning with Flexible Linguistic Rules and Approximate Evaluation of Flexible Linguistic Functions ── Reasoning and Computation with Imprecise Information and Knowledge -- Imprecise-Problem Solving and Imprecise-Knowledge Discovery ──Application of Imprecise-Information Processing -- Quantifiable Rigid Linguistic Values and Information Processing with Degrees ── Extension of Imprecise Information -- Probabilities of Flexible Events, Believability-Degrees of Flexible Propositions and Reasoning with Believability-Degrees as well as Modal Propositions.