Book excerpt: This volume contains the proceedings of the NATO-Advanced Research Workshop (ARW) "Manipulation of atoms under high fields and temperatures: Applications", sponsored by the NATO Scientific Affairs Division, Special Programme on Nanoscale Science. This ARW took place in Summer '92, in the pleasant surroundings of the Hotel des Thermes at Charbonnieres les Bains -Lyon, France. Gathering some fifty experts from different fields, the ARW provided an opportunity to review the basic principles and to highlight the progress made during the last few years on the nanosources and the interactions between atomic-scale probes and samples. The motivation is to use the novel properties attached to the atomic dimensions to develop nanoscale technologies. The perception of the atomic-scale world has greatly changed since the discovery and development, in the early 80's, of Scanning Tunneling Microscopy (STM) by Binnig and Rohrer. Beyond the observation of individual atoms, which is now routine, the concept of playing with atoms has become commonplace. This has lead to the fashioning of tools at the atomic scale, to the deposition, the displacement and the creation of atomic structures and also to the knowledge of interactions and contacts between atoms. Nanotips ending with a single atom are sources of ultra-fine charged beams. They can be unique tools for high resolution observations, for micro fabrications by micro-machining and deposition at a scale not previously attainable, with a working distance less stringent than with STM devices.