The spectral survey, carried out at the Stockholm Observatory, was initiated by B. Lindblad. The observational material was obtained by L.O. Loden, K. Loden and others in the years 1956-1965, when the Stockholm Observatory took part in a joint enterprise for using the Harvard-Boyden station. The Swedish Natural Science Research Council, the Royal Academy of the Sciences, and the K. and A. Wallenberg Foundation funded the observations, which are based on both direct and objective prism plates. The data were published in three parts, the first having less precise positions than the others. The coordinates for Catalogue I (3033) were later recomputed with the same reduction procedure as Catalogues II (3034) and III (3035), making the present catalogue uniform (Andersen, 1977). The files include star identification, finding chart identification, RA and Dec, galactic longitude and latitude, spectral type, blue magnitude, visual magnitude and remarks. The data concerning the part 2 were revised by Brian Skiff in November 1996 (see the "History" section below)