With the coexistance of magnetic and liquid properties, magnetic fluids provide the opportunity to create innovative products and solve complex technical problems. This book sets out to present the whole circle of problems connected with magnetic fluid applications: preparation of magnetic fluids, their physical properties, fluid and mechanical phenomena under the action of magnetic fields and numerous technical devices based on magnetic fluids. Therefore the book should allow pratising engineers to get basic knowledge on magnetic fluids and then to design and exploit commercial products. The fluid mechanical and magnetic phenomena are examined in detail in the book as they are the basis for all technical devices. The core of magnetic fluid technology is described in an easy-to-understand format. The design and operational principles of numerous magnetic fluid devices, such as seals, bearings, shock-absorbers, dampers, and printers are presented. New technological processes (ore separation, drag reduction, heat and mass transfer enhancement) are explained in detail with a view to assisting the user with an in-depth understanding of the technology. The last chapter of the book presents apparatus for the measurement of physical values.