This book contains the proceedings from a summer school held at IRAM in Grenoble from September 14 to September 18, 1998. The school was attended by more than 50 participants from abroad. Not all lectures have been put in written form. The school also included a general introduction to millimeter astronomy by Dr. Clemens THUM (IRAM), and a one hour lecture on astrometry by Dr. Alain BAUDRY (Observatoire de Bordeaux). A visit of the IRAM interferometer on Plateau de Bure was an essential part of the school, which gave an opportunity to the attendants to confront the concepts described in the lectures to their practical implementation on the site.
The school would not have occurred without the dedication of Mrs Catherine BERJAUD, who kindly took care of all logistics problems before and during the school.
Special thanks are also due to the staff of the Plateau de Bure interferometer, who made possible a visit to the site despite the inherent difficulties to handle such a large group of persons.
We also thank Alain PERRIGOUARD and Roger AHTCHOU for help with the video equipment which gave us a lot of fun during the ``real time'' sessions.