Preface; 1. Large-scale structure of spiral nebulae W. Baade; 2. Some remarks on multiple galaxies V. A. Ambartsumian; 3. A study of bright members of the Large Magellanic Cloud M. W. Feast, A. D. Thackeray and A. J. Wesselink; 4. On rotating ring orbits in galaxies B. Lindblad and P. O. Lindblad; 5. The distribution of atomic hydrogen in the galaxy H. C. van de Hulst; 6. Spectroscopic evidence bearing on the distribution of gas in extra-galactic systems N. U. Mayall; 7. On the role of diffuse emission nebulae in galaxies G. A. Shajn; 8. Galactic and extra-galactic radio frequency radiation due to sources other than the thermal and 21-cm emission of the interstellar gas R. Hanbury Brown; 9. The radio emission from the galaxy and the Andromeda nebula J. E. Baldwin; 10. Variable stars and problems of general structure of galaxies B. V. Kukarin; 11. The space distribution of middle- and late-type super-giants in the region of the galactic system near the sun W. P. Bidelman; 12. The observation of blue giant stars at great distances from the sun W. W. Morgan; 13. The spatial distribution of novae and super-novae I. M. Kopylov; 14. Spiral structure and the rotation of galaxies B. A. Vorontsov-Velyaminov; 15. On the structure of galaxies according to photometric studies D. E. Shchgolev; 16. Comparison of the Galactic System with other stellar systems J. H. Oort.