Recent data on isotopic anomalies of various elements in meteorites are interpreted in the picture of the birth of the Sun in a stellar OB association. The following points are suggested by this analysis. (a) The standard picture of stellar nucleosynthesis by an exponentially decreasing stellar activity throughout the galactic life remains tenable. (b) Addition of newly generated atoms takes place in spiral arms. (c) The last addition of solar system material is due to several massive supernovae (M>15M/sub sun/) exploding within the protosolar OB association. The nucleosynthetic yield of these stars is high in /sup 16/O and /sup 26/Al but very low for r- and p-process elements (C burning is probably not the main generator of /sup 26/Al). The record of the cosmic ray fluxes in the protosolar OB associations is perhaps written in hypothetical meteoretical boron isotopic anomalies.