The inspiration for this volume was a workshop held under the auspices of the PASCALNetworkofExcellence.Detailsoftheeventandmoreinformationabout the Network can be found under the heading 'Workshop Organization.'The aim of this preface is to provide an overview of the contributions to this volume, placing this research in its wider context. The aim of the workshop was to bring together researchers working on s- space and latent variable techniques in di'erent research communities in order to create bridges and enable cross-fertilizationof ideas. For this reasonwe del- erately soughtinvited refereedcontributions that wouldsurvey a broader'eld of research giving a common notation and entry point into the individual papers. The'veinvitedcontributionsare(inalphabeticalorderof'rstauthor)Avrim Blum on Random Projection, Margins, Kernels and Feature Selection,Wray Buntine and Aleks Jakulin on Discrete Principal Components Analysis, Dunja Mladeni´con Dimensionality Reduction by Feature Selection in Machine Lea- ing, Roman Rosipal and Nicole Kr¨ amer on Overview and Recent Advances in Partial Least Squares, and Mike Titterington on Some Aspects of Latent Str- ture Analysis.