Michael Dummett's new book is the greatly expanded and recently revised version of his distinguished William James Lectures, delivered in 1976. Dummett regards the construction of a satisfactory theory of meaning as the most pressing task of contemporary analytical philosophy. He believes that the successful completion of this difficult assignment will lead to a resolution of problems before which philosophy has been stalled, in some instances for centuries. These problems turn on the correctness or incorrectness of a realistic view of one or another realm--the physical world, the mind, the past, mathematical reality, and so forth. Rejection of realism amounts to adoption of a variant semantics, and often of a variant logic, for the statements in a certain sector of our language. Dummett does not assume the correctness of any one logical system but shows how the choice between different logics arises at the level of the theory of meaning and depends upon the choice of one or another general form of meaning-theory. In order to determine the correct shape for a meaning-theory, we must attain a clear conception of what a meaning-theory can be expected to do. Such a conception, says Dummett, will form "a base camp for an assault on the metaphysical peaks: I have no greater ambition in this book than to set up a base camp."