Astronomical photographs contain an enormous amount of information. This presents extremely interesting problems when one wishes to produce digitised sky atlases, to archive the digitised material, to develop sophisticated devices to do the digitising, and to create software to procecc the vast amounts of data. All these activities are necessary to be able to do astronomy. One such activity is the important, large-scale optical identification of objects which also emit radiation at other wavelengths. Other activities of the past decade include a multiplicity of surveys that have been made on galaxies and clusters of galaxies. This book treats, in five sections, the existing and future surveys, their digitisation and their impact on astronomy. It is a reference for people in the field and for those who wish to engage in using or producing sky surveys.

H.T. MacGilLIVRAY Royal Observatory Blackford Hill Edinburgh EH9 3HJ Scotland U.K. lAU Symposium No. 161 on 'Astronomy from Wide-Field Imaging', held in Potsdam, Germany, during 23-27th August 1993, was the first conference organised by the recently-formed Working Group of lAU Commission 9 on 'Wide-Field Imaging'. This Working Group was instigated during the XXIst meeting of the General Assembly of the International Astronomical Union in Buenos Aires in 1991, and represented a merging of the former formal lAU Working Group on 'Astronomical Photography' and the informal 'Digitised Optical Sky Surveys' Working Group. Dr. Richard West was 'invited' to be Chairperson, and hence was given the daunting task of organising the Group from scratch. The very fact that the first conference after only two years was a major lAU Symposium says much about the determination and enthusiasm of Richard West to fulfilling the aims of the new Working Group. The siting of the conference in Potsdam in formerly East Germany provided an excellent opportunity to advantage from the political changes in Eastern Europe. Good access to the meeting was possible by scientists from Eastern European countries, allowing exchange of information on the very important Wide-Field facilities in both East and West, information on the rich archives of photographic plates that exist in both East and West, and allowing discussions between scientists facing very similar problems in both East and West.

H.T. MacGilLIVRAY Royal Observatory Blackford Hill Edinburgh EH9 3HJ Scotland U.K. lAU Symposium No. 161 on 'Astronomy from Wide-Field Imaging', held in Potsdam, Germany, during 23-27th August 1993, was the first conference organised by the recently-formed Working Group of lAU Commission 9 on 'Wide-Field Imaging'. This Working Group was instigated during the XXIst meeting of the General Assembly of the International Astronomical Union in Buenos Aires in 1991, and represented a merging of the former formal lAU Working Group on 'Astronomical Photography' and the informal 'Digitised Optical Sky Surveys' Working Group. Dr. Richard West was 'invited' to be Chairperson, and hence was given the daunting task of organising the Group from scratch. The very fact that the first conference after only two years was a major lAU Symposium says much about the determination and enthusiasm of Richard West to fulfilling the aims of the new Working Group. The siting of the conference in Potsdam in formerly East Germany provided an excellent opportunity to advantage from the political changes in Eastern Europe. Good access to the meeting was possible by scientists from Eastern European countries, allowing exchange of information on the very important Wide-Field facilities in both East and West, information on the rich archives of photographic plates that exist in both East and West, and allowing discussions between scientists facing very similar problems in both East and West.

Astronomical photographs contain an enormous amount of information. This presents extremely interesting problems when one wishes to produce digitized sky atlases, to archive the digitized material, to develop sophisticated devices to do the digitizing, and to create software to process the vast amounts of data. All these activities are necessary to be able to carry out astronomy work. One such activity is the important, large-scale optical identification of objects which also emit radiation at other wavelengths. Other activities of the past decade include a multiplicity of surveys that have been made on galaxies and clusters of galaxies. This book treats, in five sections, the existing and future surveys, their digitization and their impact on astronomy. It is designed to serve as a reference for people in the field and for those who wish to engage in using or producing sky surveys.