In the course of the years since H. D. SCHMIDT, in 1895, describcd his "microscopic dissector," a mechanical device for dissecting and study­ ing biological materials, a great wealth of information has been pub­ lished in the scientific and technical literature on methods involving the use of exceedingly delicate microtools mechanically guided under microscopic control for the investigation of microscopic structures and very small amounts of material.. The operative tools used can be moved with considerable precision under various microscopic magnifications to perform the required tasks. With the continuous progress in these methods, hundreds of micro­ manipulators and other mechanical manipulativc devices, auxiliaryequip­ ment, and a great diversity of microtools have been described for per­ forming varied operations on practically any type of materials and test objects. Thus, micromanipulative and related techniques have become innumerable and often intricate, and the applications, formerly confined to certain fields of biology and medicine, have been extended to the most diverse fields of science and technology as mtn be Been from a rapid glance at the contents of the presEmt volume.