Enriching database models so as to allow the user to deal with fuzzy and uncertain information has been of scientists' concern for years. This resulted in numerous contributions, mainly with respect to the popular relational model or to some related form of it. The experience was instructive, although still far from concrete applications.The time has come that the advantages of object-oriented databases are acknowledged outside the research and academic worlds and a breakthrough of new commercial softwares is observed. Lately research has been devoted to the endowment of this type of databases with more real-world reflecting semantics. It proved that the object-oriented paradigm lends itself extremely well to it. This is very promising and opens new perspectives for the availability of new-generation database products in the near future.The book presents the latest research results in dealing with fuzziness and uncertainty in object-oriented databases.