This Special Issue of Journal of Optics B: Quantum and Semiclassical Optics brings together the contributions of various researchers working on theoretical and experimental aspects of cold quantum gases. Different aspects of atom optics, matter wave interferometry, laser manipulation of atoms and molecules, and production of very cold and degenerate gases are presented. The variety of subjects demonstrates the steadily expanding role associated with this research area. The topics discussed in this issue, extending from basic physics to applications of atom optics and of cold atomic samples, include:

•Bose--Einstein condensation
•Fermi degenerate gases
•Characterization and manipulation of quantum gases
•Coherent and nonlinear cold matter wave optics
•New schemes for laser cooling
•Coherent cold molecular gases
•Ultra-precise atomic clocks
•Applications of cold quantum gases to metrology and spectroscopy
•Applications of cold quantum gases to quantum computing
•Nanoprobes and nanolithography.

This special issue is published in connection with the 7th International Workshop on Atom Optics and Interferometry, held in Lunteren, The Netherlands, from 28 September to 2 October 2002. This was the last in a series of Workshops organized with the support of the European Community that have greatly contributed to progress in this area. The scientific part of the Workshop was managed by A Hemmerich, W Hogervorst, W Vassen and J T M Walraven, with input from members of the International Programme Committee who are listed below. The practical aspects of the organization were ably handled by Petra de Gijsel from the Vrije Universiteit in Amsterdam.

The Workshop was funded by the European Science Foundation (programme BEC2000+), the European Networks 'Cold Quantum Gases (CQG)', coordinated by E Arimondo, and 'Cold Atoms and Ultraprecise Atomic Clocks (CAUAC)', coordinated by J Henningsen, by the German Physical Society (DFG), by the Dutch Foundation for Fundamental Research on Matter (FOM) and by the Dutch Gelderland province. We thank all these sponsors and the members of the International Programme Committee for making the Workshop such a success.

At this point we take the opportunity to express our gratitude to both authors and reviewers, for their efforts in preparing and ensuring the high quality of the papers in this special issue.

Wim Vassen  Vrije Universiteit, Amsterdam
Andreas Hemmerich  Universität Hamburg
Ennio Arimondo  Università di Pisa
Guest Editors

International Programme Committee
A Aspect  Orsay, France
E Cornell  Boulder, USA
W Ertmer  Hannover, Germany
T W Haensch  Munich, Germany
A Hemmerich  Hamburg, Germany
W Hogervorst  Amsterdam, The Netherlands
D Kleppner  Cambridge, USA
C Salomon  Paris, France
G V Shlyapnikov  Amsterdam, Paris, Moscow
S Stringari  Trento, Italy
W Vassen  Amsterdam, The Netherlands
J T M Walraven  Amsterdam, The Netherlands