In response to a growing interest in total least squares (TLS) and errors-in-variables (EIV) modelling by researchers and practitioners, well-known experts from several disciplines were invited to prepare an overview paper and present it at the third international workshop on TLS and EIV modelling held in Leuven, Belgium, August 27-29, 2001. These papers, representing two-thirds of the book, together with a selection of other presented contributions yield an overview of the main scientific achievements since 1996 in TLS and errors-in-variables modelling. The book not only deals with computational issues, as it also describes statistical, numerical and algebraic properties, as well as many new generalizations and applications.