This laboratory guide comes at a time when several other method books have already been published in this field. Is this one different from the others? Yes and no. There was no attempt made to be comprehensive. Rather, data were brought to bear on areas where enough competence has been gathered in our laboratories and to complement recent method books (many of which cover extensively various aspects of molecular biology) in those matters which appeared to us somewhat neglected. There was a constant preoccupation and effort to provide miniaturized proce dures that are both simple and time-saving. Interest was devoted to standardized procedures and culture conditions, avoiding dogmas such as those giving excessive importance to sophisticated culture media with endless adjustments for local or personal considerations. The key to success is the quality of the plant material serving as a source of cells. Consequently, isolation. extraction or culture techniques can be simplified and standardized. This is symptomatic for our times as it marks the end of a period when methodological matters were frequently above the biological problems. The times of "methods above all" is basically over, despite the fact that many of us still believe that, say, tissue culture is a "science" per se. By presenting a few original techniques we believe that one seriously reduces the empiricism still prevailing in this area of research.