"... this book is a useful contribution to work in the area ... This is a highly technical, mathematically oriented book addressing a specialised interest area. Its strength lie in its bringing together a diversity of recent research work and putting this work in a contextual framework. An excellent feature of the book is its comprehensive, up-to-date references ... The book finally comes across as a useful, if somewhat confusing to read, summary of recent work and knowledge in a highly specialised technical interest area." Jonathan O'Brien Newsletter of the Australian Robot Association, 1994