The purpose of this report, which is based on an unpublished draft prepared in the 1970s, is to provide seismologists with the information they may need to use the WWSSN data set as it becomes available in a more easily accessible and convenient format on the Internet. The report includes a description of the WWSSN network, station facilities, operations and instrumentation, a derivation of the instrument transfer functions, tables of transfer functions, a description of calibration techniques, and a description of a method used to determine important instrument constants using recorded calibration data.