Solid state detectors, which are basic research instruments in low energy nuclear physics have not been very much in use in the past for experimental high energy physics. It is only in the last 13 years that their possibilities have been really explored, with increasing interest, and their development has been so successful as to make it now very plausible that the next generation of experiments will heavily rely on such detectors in order to achieve the requested space resolution. Silicon detectors were used for the first time in a high energy experiment in 1968 as active (“live”) targets in the study of diffractive hadron excitations [1,2]. The basic aim was to measure the recoil of the nucleus on which the reaction had taken place, identifying in this way the nature of the interaction, i.e. separating coherent and incoherent events. In the first section we describe a few of the problems encountered in this work since the solution found for these problems led to the construction of the first silicon detector telescopes, while section 2 deals with a more technical description of the performances of these detectors. The discovery of charmed particles opened, in the mid-seventies, a new field of application for solid state detectors: the measurement of the lifetime of heavy, weak decaying particles such as the D-mesons. In this case the physical information requested from a successful detector is much more detailed: one requires not only the selection of coherent events out of the incoherent background, but also a precise definition of the production and decay points of a meson with a space resolution suitable for measuring its path. This subject is described in some detail in section 3, since the first results of such measurements are actually presently appearing. In previous applications the silicon detector has always been a thin sheet of pure crystal, sandwiched by metal walls in order to obtain a depleted region and to collect the ionization charges. Progress in the technology of these detectors has opened a new possibility: to structure the electrodes into thin strips and to operate the detector as a fine grained proportional chamber, able to provide a resolution which, in principle, can reach 10—20 p~m. Section 4 describes what has been achieved in this direction during the last two years, while the last section shows the development, now in progress, of high resolution solid state detectors either for