"With the development of society and the great increase of knowledge and information, more and more decision-making problems involve a number of decision makers (DMs). The subjective preference of DMs reflects a particular analysis, thinking process, and cognitive activity of the decision-making problem. Because the uncertainty of the decision-making environment, DMs tend to express their preference with interval numbers, fuzzy numbers, and linguistic variables. As a result, several uncertain preference styles, such as judgment matrix, utility value, and preference ordering value of interval numbers, fuzzy numbers and linguistic term set are given by DMs. Owing to the many assessment factors involved in complex decision-making problems, the difference of preferences, and the impact of the internal and external environment, it is often difficult to aggregate information in the group decision-making process. The studies on group decision making are reviewed in Chapter 1. The consistency measuring and ranking methods of interval number reciprocal judgment matrix and interval number complementary judgment matrix are discussed in Chapter 2. An unascertained number preference and a three-point interval number preference are presented in Chapters and 4, and their consistency and developed ranking method of the alternatives are also defined. The linguistic preference is studied in Chapter 5, and two consistencies definitions have been put forward. The aggregating methods of several uncertain preferences are discussed in Chapter 6. The multistage aggregating model of uncertain preference is studied in Chapter 7. An aggregating model of multistage linguistic information based on TOPSIS is proposed in Chapter 8"-- Provided by publisher.