Neutron spectra have been measured by the foil-activation method in 13 different environments in and around the Sandia Pulsed Reactor, the White Sands Missile Range Fast Burst Reactor, and the Sandia Annular Core Research Reactor. The spectra were obtained by using the SAND11 code in a manner that was not dependent on the initial trial. This altered technique is better suited for the determination of spectra in environments that are difficult to predict by calculation, and it tends to reveal features that may be biased out by the use of standard trial-dependent methods. For some of the configurations, studies have also been made of how well the solution is determined in each energy region. The experimental methods and the techniques used in the analyses are thoroughly explained. C. Holm, who counted the foils and reliably reduced the data to activity levels, provided the essential information on which this work is based. T. Luera and G. Can0 provided the encouragement and advice which kept the authors going. Our colleagues in other laboratories provided not only ideas and valuable advice, but also gave us reciprocal experimental data for the interlaboratory comparisons of spectra. In this area we particularly thank W. Sallee, J. Meason, and M. Flanders of the White Sands Missile Range, and C. Heimbach from the Aberdeen Proving Ground.