Dr. J. S. Laskowski has written several papers on frother-collector interactions and the effect of such interactions on flotation kinetics, and on frothers chemistry and frothing. He is founder and Editor-in-Chief of the journal, Coal Preparation. Dr. E. T. Woodburn has published numerous papers on flotation froth and flotation kinetics. Frothing in Flotation, published in honor of Jan Leja, appeared in 1989. Many important contributions on various aspects of flotation froth properties and behavior and the relationship between froth appearance and flotation performance have appeared since, and this volume intends to summarize these achievements. Flotation kinetics involves a number of mass transfer processes with some of them being critically determined by the behavior of froth. Since froth is complex, and controlled experimentation is difficult, the froth phase was, until recently, either ignored or treated entirely empirically. With wide applications of flotation columns, the behavior of the froth is now often recognized as being dominant in determining flotation performance, and the research in this area is one of the most actively pursued.