[en] The mechanics and electronics of recoil-proton spectrometers for use in fast-neutron spectroscopy are described. The spectrometers include gas-filled proportional counting systems, using hydrogen and methane, and NE-213 scintillation counting systems. Computer analysis techniques for reduction of raw neutron data obtained from the spectrometers are discussed. Experiments have been conducted at the ANL Zero Power Plutonium Reactor, to measure the fast neutron spectrum in the energy range above 1 MeV. The reactor is described. The spectroscopy experiments use the aforementioned spectrometer systems to produce data. The data is further processed by described computer codes. A description of the experimental procedure is presented which involves evaluation of the systems, physical set-up, and the data gathering techniques. Comparisons are made with existing neutron data in the energy range of interest to assure proper system functioning. The results of the spectroscopy experiments are presented as leakage spectra from three reactor regions in the form of flux versus energy