In sign languages of the Deaf, now recognized as fully legitimate human languages, some signs can meaningfully point toward things or can be meaningfully placed in the space ahead of the signer. Such spatial uses of sign are an obligatory part of fluent grammatical signing. There is no parallel for this in vocally produced languages. This book focuses on American Sign Language to examine the grammatical and conceptual purposes served by these signs. It guides the reader through the various types of directional signs, the types of spatial representations signs are directed toward, how such spatial conceptions can be represented in mental space theory, and the conceptual purposes served by these signs. The book explains how the pointing behavior of signs accomplished functions that must be accomplished by any language, spoken or signed. It demonstrates an integration of grammar and gesture in the service of constructing meaning. These results also suggest that the concept of "language" has been much too narrow and that a more comprehensive look at vocally produced languages will reveal the same integration of gestural, gradient, and symbolic elements. Three appendixes contain notational conventions (identifying signs), notational conventions (direction and placement), and main types of spaces discussed. (Contains approximately 180 references.) (SM)