This book documents the proceedings of the Symposium on Particles in Fluids: Detection, Characterization and Control held as a part of the 18th Fine Particle Society meeting in Boston, August 3-7, 1987. This was the Premier symposium on this topic and the response was so good that we have decided to organize it on a biennial basis and the second symposium will be held under the rubric Particles in Gases and Liquids: Detection, Characterization and Control at the 20th Fine Particle Society meeting in Boston, August 22-26, 1989. In the modern manufacture of sophisticated and sensitive microelectronic components and other precision parts, there has been a great deal of concern about yield losses due to micrometer- and submicrometer-sized particles. These particles can originate from a number of sources including fluids, i. e. , gases and liquids used in the manufacturing process. So the detection, characterization and control or removal of these undesirable particles is of cardinal importance and this symposium was conceived and o~ganized with this in mind. The purposes of this symposium were to bring together those actively involved in all aspects of particles in fluids, to provide a forum for discussion of the latest techniques for the detection, characterization and control of particles, and to highlight areas which needed intensified R&D efforts. The printed program contained a total of 46 papers and a variety of topics dealing with various ramifications of particles in fluids were presented.