Inperplanetary magnetic field data from 10 Imp, Aimp, and Heos spacecraft have been merged into a composite data set spanning 1963--1974. A consideration of the mutual consistency of the individual data sets reveals agreement typically to within 0.2 &ggr;. Analysis of the composite data set reveals the following: (1) Although the yearly averaged magnitudes of all field vectors show virtually no solar cycle variation, the yearly averaged magnitudes of positive and negative polarity field vectors show separate solar cycle variations, consistent with variations in the average azimuthal angles of positive and negative polarity field vectors. (2) There is no heliolatitude dependence of long-time average field magnitudes. (3) Field vectors parallel to the earth-sun line are on the average 1 &ggr; less in magnitude than field vectors perpendicular to this line. (4) The heliolatitude-dependent dominant polarity effect exhibits a complex sign reversal in the 1968--1971 period and a measure of symmetry in 1972--1974 not found in earlier data.