It is our pleasure to present the 53rd volume of the Biotechnology in Agric- ture and Forestry (BAF) series. This is the second issue of the BAF series edited by the new editorial team consisting of Professors Horst Lorz, University of Hamburg, Hamburg, Germany, Jack Widholm, University of Illinois, Urbana, USA,and Toshiyuki Nagata,University of Tokyo,Tokyo,Japan. This series was originally founded by the late Professor Y. P. S. Bajaj,Delhi,India,in 1986. The current volume is somewhat unique, since in this volume only one plant cell line,the tobacco BY-2 cell line,is handled,while previous volumes mainly dealt with plants having certain economical importance. Nonetheless, the three editors of this volume,Professors Dirk Inze,Seiichiro Hasezawa and Toshiyuki Nagata,believe that most scientists who are working in the ?eld of plant s- ences will enjoy seeing this volume as a kind of source book of the unique tobacco BY-2 cells. Indeed,tobacco BY-2 cells have,over the years,gained the status as a model plant system,comparable to HeLa cells for human research. The current book is very timely because a wealth of basic knowledge on plant cells related to,e. g. ,cell division,cytoskeleton,cytokinesis,plant hormone s- naling,etc. ,has been gathered from experiments with this cell line. As re?ected in the contents,the accumulated knowledge of the BY-2 cell line is enormous and there is no other cell line that has been so important for progress in the plant sciences. Such knowledge should be shared with scientists from the ?elds of both applied and basic plant science.